1. How does the magnitude of tension electric field() from the distance to the center of a uniformly charged hollow sphere (- sphere radius)? At< () = , при > () = .

2. An equipotential surface is a surface, at each point of which ... the potential has the same

magnitude, the electric field strength vector is normal to the surface.

Which figure correctly represents the potential graph for case 1< 0,2 > 0? 3.

A charged soap bubble inflates. How will it change electrical capacitance and Electric Energy? Capacity

increases, energy decreases.

Electric current density in a medium with specific conductivity and resistivity at tension

electrostatic field and the field strength of third-party forces is equal to

[ + side ].

Two conductors with a resistance of 2 ohms and 6 ohms are connected in series. Voltage drop on the first conductor

equals 5V. Find the voltage drop across the second conductor. = ;

6Ω5V = 15V.

How will the modulus and direction of the forces of interaction of two small metal balls of the same

diameter, having charges -20Ncl and +10Ncl, if the balls are brought into contact, and then moved apart to the former

distance? The module will decrease, the directions will change to the opposite ones.

In an inhomogeneous electric field, an electric dipole unfolds its dipole moment ... along

direction of the field lines and is drawn into the region of a stronger field.

The magnitude of the intensity and the potential of the field of a point charge depending on the distance from the charge to the point

observations behave like this: ~

With an increase in the electric field strength in a certain region by a factor of three, the volumetric energy density

electric field ... increases 9 times.

Two conductors with the same cross section and different conductivities 1

and 2 connected

sequentially. What is the ratio of the electric field strengths 1 in both conductors? .

6. In the field between the plates flat capacitor a charge of 0.2 μC is acted upon by a force of 50 μN. To what voltage is the capacitor charged if the distance between the plates is 0.03 m? = ; = ; ==. = . AT.

1. An infinite uniformly charged hollow cylinder is given. How will the magnitude of the electric field inside the cylinder change in the direction from the axis to its boundary? = .

2. Compare the fluxes Ф of the field strength vector of identical point charges q for four closed surfaces shown in the figure. F = F = F = F.

3. How will the modulus and direction of the forces of interaction of two small metal balls of the same diameter with charges change-20nC and +10nC if the balls are brought into contact and then moved apart to the same distance? The module will decrease, the directions will change to the opposite ones.

4. An infinite plane-parallel plate of a homogeneous isotropic dielectric with permittivity is placed in a homogeneous electric field strength, perpendicular to the plane of the plate. What is the electric field strength inside the plate? .

5. The current density is proportional to the speed of the directed movement of current carriers in the conductor. The coefficient of proportionality is equal to ... the product of the carrier concentration and the charge of the current carrier.

6. In the circuit shown in the figure, through the resistance 1 current flows1 = 1. What current flows through resistance2,

if resistance 2 is three times greater than resistance 3? = + ; = ; = ; =; = ; = ; = ; = + = = ; = = . .

1. An electrostatic field is created by a point charge located at the origin. The charge q can be moved from points K to points M, N and L. In which case will the work of external forces against the forces of the field be maximum? K.N.

2. Charged flat air condenser. Then, without changing the charge, the distance between the plates was tripled and the entire space between the plates was filled with a dielectric (= 3). How has the energy of the capacitor changed? Hasn't changed.

3. The interaction energy of two equal point charges of the same sign, located at a distance L from each other,

expressed by the formula ….

4. How will the field strength inside a flat capacitor connected to a source change if the distance between the plates is halved? Will not change.

5. The figure shows two connection diagrams for four identical resistances. Determine the ratio of the resistance of section AB to the resistance of section CD. .

6. The radius of a uniformly charged hollow sphere is 3cm. Find the potential ratio 1 at the points of the field located

at a distance of 1 cm and 4 cm from the center of the sphere. =		; inside the sphere = on the surface =

1. Equal charges are located in the plane of the square, as shown in the figure. What is the direction of the electric field strength vector in the center of the square? Way down.

2. If the algebraic sum of the charges enclosed inside a closed surface is equal to zero, then the flow of the intensity vector through this surface is equal to zero.

3. The intensity vector and potential of the electric dipole field, depending on the distance from the dipole to the observation point, behave as follows: 2. ~ ; ~ .

4. Two infinite parallel planes are uniformly charged with equal surface charge densities. Determine the correct variant of the dependence of the potential of the electrostatic field on the coordinate. 3.1.

5. The current density in the conductor is proportional to the strength of the electric field. The coefficient of proportionality is called ... specific conductivity.

6. A uniform electrostatic field with a strength of 0.1 kV / m does 10 mJ work to move a positive charge along the lines of tension at a distance of 1 m. Determine the value of positive

1. Can the electric field outside of the system of two unlike and uniformly charged infinite parallel planes be different from zero? No.

2. A sphere uniformly and positively charged by volume is immersed in a liquid dielectric. How will the strength of the electrostatic field outside the ball change in the direction from the boundary to infinity? You need to know the dielectric constant of the dielectric.

3. The potential of the dipole field is zero (at zero potential at infinity) ... not at any point in space.

4. In an external electric field ... the polarization vector of polar and non-polar dielectrics is nonzero.

5. The work done by external forces when moving a positive charge along a section of the circuit is numerically equal to ... the product of the charge by electromotive force on this area.

6. The bird sat on a wire carrying a current of 2 kA. Wire resistance per meter length is 2.5 10−5 Ohm, the distance between the paws of the bird is 5cm. What voltage is she under? = = . .

− = .− = . AT.

1. Choose the correct statement. The equipotential surfaces of an electrostatic field are always perpendicular to the lines of tension.

2. In the common center of two cubes with edges equal to 1 and 2, there is a point charge +Q. Compare the fluxes of the field strength vector of this charge through the faces of the cubes. The flows are the same and not equal to zero.

3. The potential difference between two points is … ∫ .

4. Indicate the number under which both physical quantities are vectors: electric displacement (induction), dipole moment.

6. Five lamps with a resistance of 440 Ohm are connected in parallel and connected to a 220V network. Find the power

consumed by lamps. = = = = B;									Ohm; = Ohm; = = = . ; =

Sergei Sergeevich's answers. I do not vouch for the correctness

A metal ball with a radius of 10 cm is charged to a potential of 1500 V. How much heat will be released when it is grounded?

C ball = 4pi*E*R = 4*3.14*8.85*0.1*10^(-12) = 1.1121*10^(-11) Farad

Q \u003d C * (U ^ 2) / 2 \u003d 0.000012511 J.

A flat air capacitor was charged and not disconnected from the voltage source. Then the entire space between its plates was filled with a dielectric with permittivity e=4. How does this change the energy of the capacitor?

Not disconnected from the power supply => U = const. W cond \u003d C * (U ^ 2) / 2. C \u003d e * E * S / d. e1 = 1; e2 = 4; Increased 4 times.

The circulation of the tension vector is 0 for...

The circulation theorem in electrostatics: the circulation of the electrostatic field strength vector along any closed loop is zero. ...for any electric field.

The dielectric constant e is greater than unity in the case of ...... For any dielectrics.

With one resistance of the rheostat, the voltmeter shows 6 V, the ammeter 1 A. With a different resistance of the rheostat, the instrument readings: 4 V and 2 A. Determine internal resistance current source.

In general: e*R+r = I<=>e = R*I+r*I<=>e = U+I*r. From the conditions we get the system: (e = U1+I1*r; e = U2+I2 r => U1+I1*r = U2+I2*r, r(I2-I1) = U1 -U2, r = (U1-U2)/(I2-I1), r = 2 ohm.

Point K is at a distance of 4 m, and point M is at a distance of 2 m from a point charge of 200 nC. Find the potential difference between points K and M. uk - um = k*q/rm - k*q/rk = kq(rk-rm)/(rk*rm) = -450 V.

The strength of the electric field is numerically equal to ...... the force acting on a unit point charge located at a given point in the field.

The radius of a charged metal ball is 10 cm. The radius of the ball was increased by 3 times while maintaining its charge. How many times has the field strength changed at a distance of 50 cm from the center of the sphere? Will not change

A charge q is placed in the middle between two point charges q = 12nC and q2 = -4nC. A force of 6 μN acts on this charge from the charge q2. Determine the force acting on the charge q from both charges q1 and q2.12 μN

The electric dipole at the initial moment is located in a uniform electric field so that its dipole moment is perpendicular to the field lines. What happens next with the dipole? It turns around so that its dipole moment is directed along the field, then stops.

A flat capacitor with capacitance C is connected to a voltage source with EMF e. What work must be done to double the distance between the capacitor plates? A = W1 - W2 = (e^2)*q/2d - (e^2)*q/4d = (e^2)*q/4d = (e^2)*C/4.

The electric energy of a charged ball is 0.15 mJ, its charge is 10 μC. Determine to what potential the ball is charged.

W = q * u / 2 => u = 2W / q = 30 V.

Which line correctly indicates the directions of a) the vector of the electric field strength created by the dipole at point A and b) the vector of the dipole moment? p = q*l; vector l: "+"->"-" The intensity of the dipole field on the perpendicular raised to the axis from its middle is opposite to the vector p.

The electrostatic field is created by a system of two metal balls with charges -4q and -q. Specify the point at which the field potential can be zero. There is no such point.

At some point of an isotropic dielectric with permittivity e, the electrical displacement (induction) has the value D. What is the polarization P at this point? D = e*E+P => P = D/(e*E) // Not entirely sure

Three resistors with resistance R1 = 1 ohm, R2 = 2 ohms, R3 = 3 ohms are connected in parallel in the circuit direct current. What is the ratio of the powers dissipated in these resistors? Resistor power in DC circuit P = I^2*R serial connection=> I is the same 1:2:3

Uniform field strength E=80kV/m. Determine the potential difference between points 2 and 1 if the distance between them is 5 cm and the angle b = 60*? U12 = E*l*cos(b) = 2000V

The electric field is created by a volumetrically charged ball with the same volumetric charge density. At some measurement point located inside the ball, the field strength is determined. How will this tension change when the distance from the center of the ball to the point of observation decreases by a factor of 2? Inside the ball E = p*r/(3*e0*e1). Decrease by 2 times

The charge of the ball is 10 μC, its electrical energy is 0.15 mJ. Determine to what potential the ball is charged. W = q*u/2 => u = 2W/q. 30 V

Choose the correct statement to change the force of interaction of two point charges when they are transferred from vacuum to a homogeneous isotropic dielectric (e=2). According to Coulomb's law, the force of interaction of two point charges is directly proportional to the product of the charges, inversely proportional to the square of the distance between them and the dielectric constant of the medium => In a dielectric, the force will decrease by 2 times.

The current source with internal resistance r is closed to the load resistance R. Which or which of the graphs qualitatively correctly reflect the dependence of n (the efficiency of the current source) on R? n = U/E = IR/(I(R+r)) = R/(R+r); R -> inf; n -> 1; But at the same time, the current in the circuit is small and the power is small.

Two light bulbs with a resistance of 6 ohms and 1.5 ohms are connected in turn to a certain current source and consume the same power. Determine the internal resistance of the current source. P1=P2; (1) P = I^2*R = e^2*R/((R+r)^2)

(2) (2) in (1) + cancel e^2: R1/(R1+r)^2 = R2/(R2+r)^2 express r: r = sqrt(R1*R2); r = 3 ohm

What resistance should be connected in parallel to the resistance of 21 ohms so that the resistance of the section is

6.3 ohm? 1/R = 1/R1 + 1/R2; R2 = R1*R/(R1-R); R2 = 9 ohm

The electric field is created by a uniformly charged hollow sphere. At some measurement point located outside the sphere, the field strength is determined. How will this tension change when the distance from the center of the sphere to the point of observation is doubled? Decrease by 4 times

The equipotential surfaces of the field of a point positive charge have the form of ... concentric spheres

An isotropic dielectric (permittivity e) in the form of a right parallelepiped is located in a uniform electric field, and the field lines are perpendicular to one of the faces. Determine how the magnitude of the field strength E and electric induction D in a dielectric will change compared to vacuum. E = E0 - sigma/e0; E0 -- external field, sigma -- surface charge density. D = e*e0*E There is no final answer.

The electric current density in a homogeneous conductor with an increase in the electric field strength by a factor of 2... j = sigma * E, where sigma is the specific conductivity of the medium. Will double.

On the resistance R, when an electric current I flows through it for a time t, the amount of heat Q is released, for which the following expression is valid: Q = I ^ 2 * R * t

A battery of two 200 nF capacitors connected in series is supplied with a voltage of 300 V. Find the energy stored in the battery. C \u003d C1 * C2 / (C1 + C2) \u003d 100nF. W \u003d C * U ^ 2 / 2 \u003d 50 * 300 ^ 2 * 10 ^ (-9) \u003d 4.5 * 10 ^ (-3) J

If the potential of the electric field at infinity is zero, then at any point in the field the potential is numerically equal to ... the work of the field in moving a unit positive charge from a given point of the electric field to infinity

Two point charges of the same name approach each other, sliding along an arc of a circle. How does the intensity and potential of the field change in the center of this circle? The magnitude of the tension increases, the potential does not change (This is due to the fact that the tension has a vector superposition, and the potential has a scalar one).

A flat air capacitor was charged and not disconnected from the voltage source. Then the distance between the plates was increased by 2 times. How did this change the energy density of the field of the capacitor. Unchanged w = W/Sd=1/2 * CU^2/(Sd) Given that C = Eps*Eps*S/d (Eps=Epsilon) and U=Ed, w = Eps*Eps*E ^2/2 This function does not depend on the distance between the plates.

According to the Joule-Lenz law, the power released on the resistance R when current I flows through it and voltage U drops on it is equal to: U ^ 2 / R

The normal n to the flat area dS makes an angle alpha with the electric field density vector j. Choose the correct expression for the current through the pad. j * dS * sin(alpha) (j is normal with respect to dS)

Three identical capacitors are connected once in series, the other in parallel. What is the ratio C2/C1? 1/9 For the first case (in series), 1/C1=1/c+1/c+1/c=3/c => c1=c/3 For the second case (in parallel), C2=C+C+C \u003d 3C But you can share it yourself.

Compare fluxes Ф of the field strength vector of identical point charges q for four closed surfaces

3 F1 = f4> F2, F3 = 0

In a closed circuit, positive free charges - 1 move in the direction of increasing potential in the area of ​​action of external forces, and in the area of ​​action of electrostatic forces - in the direction of decreasing

The vector of the strength of the electrostatic field in relation to the lines of tension directed - 5 tangentially in the direction of decreasing potential.

A dielectric ball in an inhomogeneous electric field - 3 will move to the left

How will the field strength change inside a flat capacitor, charged and disconnected from the source, if the area of ​​​​the plates is doubled - 4 will decrease by 2 times

What happens to the voltmeter readings and the brightness of the bulb when the rheostat is shifted to the right - 3 readings increase, the brightness decreases

Two capacitors C1 and C2 are connected in series. The total capacitance C "is 3 uF. Determine the value

capacitance C1, if C2 = 4 uF solution: 1 / C "= 1 / C1 + 1 / C2 C" = C1 * C2 / (C1 + C2) C1 = 12 uF

1. Homogeneous lines of force magnetic field perpendicular to the plane of the circuit (from us to the drawing), the current in which is directed clockwise. The Ampère force acting from the side of a uniform magnetic field on the circuit ... tries to stretch the circuit in its plane.

2. Choose the correct expression for the magnetization vector.∆ ∆ .

3. is the magnetic susceptibility of diamagnets, magnetic moment their atoms. Which statement is correct?< , | | , = .

4. The rate of change of the magnetic flux penetrating the circuit is numerically equal to ... EMF induced in the circuit.

5. Indicate the line that correctly represents the expression for the Lorentz force and the rule that should be followed when determining the direction of the force vector for a positive charge. , left hand rule.

6. What is the period of the oscillation described by the equation = 2 sin(2 + ⁄6)? From the condition = . = √ , = =

√ , √ = = , = = s.

1. The value of the vector of magnetic induction of the field of infinite direct current depends on the distance between the observation point and the conductor with current as follows ... ~ ⁄.

2. The flow of the magnetic induction vector (magnetic flux) through a closed surface is equal to ... zero.

3. Which formula correctly describes the energy of the magnetic field created by a circuit with current and inductance (

is the total magnetic flux penetrating the circuit)? = .

4. The nature of the EMF of induction during the movement of a conductor in a constant magnetic field is due to the force ... Lorentz.

5. 1st year NRU ITMO wrote out the following Maxwell equations in

6. A straight conductor with a length of 40cm and a current of 2.5A is placed in a homogeneous magnetic conductor with an induction of 0.07T. Determine the force acting on the conductor from the side of the field if the direction of current movement makes an angle of 30 ° with the lines of force.

1. From the proposed list, select vector quantities: magnetic induction, current strength, magnetic moment, flux Ф of the magnetic induction vector. , .

2. Two mutually perpendicular conductors with equal currents lie in the same plane. Indicate the points at which the magnetic field induction is equal to zero. 1 and 3.

3. How will the magnitude of the magnetic field strength inside the solenoid change if a magnet with permeability = 9 is removed from it? Decrease by 9 times.

4. What number correctly describes the expressions that determine: a) the coefficient of mutual induction 12 and b) the energy of the magnetic field created by two circuits with currents 1 and 2 (2 is the total magnetic flux penetrating the second

circuit due to the current of the primary circuit,

- inductance, respectively, of the first and second circuits)? =

5. A beam of positively charged particles flies into a uniform electric field perpendicular to the vector. How should the magnetic induction vector be directed to compensate for the deviation

beam generated by an electric field? The vectors shown in the figure lie in the plane of the drawing. Per

6. A weight suspended from a spring oscillates vertically with an amplitude of 4 cm. Determine the total vibration energy of the weight if the spring constant is 1 kN/m. full \u003d kin + sweat \u003d + . At the moment of maximum displacement = .

Therefore, at this moment

= = . .

1. What physical quantity has a dimension in SI units equal to C B?

2. The figure shows sections

two parallel

straight long

conductors with oppositely directed currents 1 and 2,

with 1 = 22 .

The magnetic induction of the resulting magnetic field is zero in some

interval point…d.

3. The coefficient of mutual induction of two circuits with current in vacuum depends only on ... the size, shape of the circuits, the distance between them and their relative orientation.

4. Which line correctly reflects the properties of diamagnets and their constituent molecules (- magnetic susceptibility)? The value is small and negative, the intrinsic magnetic moment of the molecules is equal to zero.

5. Under what number is the inductance of the solenoid correctly represented (- relative magnetic permeability, 0

- magnetic constant, - number of turns per unit length of the solenoid, - its length, - cross-sectional area, the length of the solenoid is many times greater than its diameter)? = .

6. A material point with a mass of 20 g oscillates according to the law = 0.1 cos (4 + 4), m. Determine the total energy of this point. full \u003d kin + sweat \u003d +. At the moment of passing the equilibrium state, the displacement is equal to zero = , and

speed is maximum. Therefore, at this moment

= ′ = − . (+). From here

the maximum value of the modulo speed will be equal to. ; Consequently,

1. Two infinitely long parallel conductors with currents approach each other, moving along an arc of a circle. How does the magnetic field induction modulus change at the center of this circle for the case of parallel and for the case of antiparallel conductors? The plane on which the circle is located is perpendicular to the conductors with current. For parallel increases, for antiparallel decreases.

2. The lines of magnetic induction of the field of infinite direct current have the form of ... concentric circles.

3. Indicate the expression that determines the dependence of the magnetic susceptibility on temperature for paramagnets ( is the Curie constant). = /.

4. How does a uniform magnetic field with induction act on a rectangular loop with current? Turns the frame towards us.

5. The oscillatory circuit consists of an inductor and two identical capacitors connected in parallel. How will the oscillation period of the circuit change if the capacitors are connected in series? Decrease by 2 times.

6. One mathematical pendulum has a period of 3s, the other 4s. What is the period of oscillation of a mathematical pendulum, length

1. The unit of measurement of magnetic induction is ... Tesla.

3. The flow of the magnetic induction vector through a closed surface ... is always equal to zero.

4. The magnetic flux penetrating the coil changes over time according to a graph. In what interval does the induction EMF have a minimum value in absolute value, but not equal to zero? − .

5. At the exam testing in physics, a student 1st year SPbGUITMO presented the following Maxwell equations in integral form. Did he make a mistake in them, and if so, in what equation?

6. A weight of 250 g, suspended from a spring, oscillates vertically with a period of 1 s. Determine the stiffness of the spring. =

1. Choose the correct expression for the magnetic field vector. − .

2. The induction vector of a uniform magnetic field is directed from left to right. A conductor with direct current is located perpendicular to the plane of the figure (the current flows from us). Choose a point where the total induction can be zero. four.

3. How will the energy stored in the magnetic field of the solenoid change if the solenoid current is halved and the solenoid inductance doubles at the same time? Decrease by half.

4. In an external magnetic field 0 placed a glass of water, the molecules of which do not have their own magnetic moment. What will be the magnitude of the magnetic field in water and how will the magnetization vector of water be directed? will become less

by fractions of a percent, the vector will be directed along the vector.

5. A beam of positively charged particles passes through uniform electric and magnetic fields directed perpendicular to the beam motion. How should the magnetic induction vector be directed in order to compensate for the beam deflection created by the electric field? In the positive direction of the axis.

6. A point charge flies at a speed of 15m/s into a uniform magnetic field with an induction of 2T. The vector of velocity and magnetic induction makes an angle of 30°. The magnitude of the Lorentz force acting on the particle from this field is 0.5 mN.

1. The unit of measurement of the self-induction EMF is ... Volt.

2. Two straight conductors 1 and 2 with currents, respectively, 1 and 2 are parallel. What is the direction of the magnetic field created by the first conductor in the place where the second conductor is located, and how is the Ampere force acting on the second conductor directed? directed behind the drawing, directed upwards.

3. How will the energy stored in the magnetic field of the solenoid change if the solenoid current doubles and at the same time the solenoid inductance decreases fourfold? Will not change.

4. A positively charged particle moves from an infinite current-carrying conductor. The force acting on the particle will ... decrease, deflecting the particle upward.

Which of the formulas represents the equation of damped oscillations (- damping coefficient, 0

- own

oscillation frequency)? ′′ +′ + = .

A charged particle moves in a uniform magnetic field along a circle of radius 1 . After increasing the field induction

and the speed of the particle is 2 times the radius of the circle became. Find an attitude

1. Homogeneous is the magnetic field... inside an infinite solenoid.

2. Indicate the direction of the force acting on a conductor with current density. 5.

3. In an external magnetic field 0 placed a piece of paramagnetic aluminum. What will be the magnitude of the magnetic field inside aluminum and how will the aluminum magnetization vector be directed? becomes larger by a fraction of a percent, the vector will be directed along.

4. What is the rule for the direction of Foucault currents? Lenz's rule.

5. Which of the formulas represents the equation forced vibrations(- attenuation coefficient, 0 – natural frequency of oscillations, – value proportional to the amplitude of the driving force, – frequency of the driving force)?′′ +′ + = .

6. Flat conductive circuit with an area of ​​100cm 2 is located in a magnetic field perpendicular to the magnetic lines of force. The magnetic induction changes according to the law = (1 − 32) 10−3 T. Determine the EMF of the induction that occurs at time = 2s. = −Ф = − = −− − (−) =− = , mV.

1. A circuit with current is in a magnetic field, - its magnetic moment, max is the maximum torque, min is the minimum torque. The magnitude of the magnetic induction vector is…max ⁄.

2. From the values ​​listed below, select the one on which the inductance of the solenoid in a non-ferromagnetic medium does not depend. Depends on the number of turns per unit length, the cross-sectional area of ​​the solenoid, the length of the solenoid, and the magnetic permeability of the medium.

3. Which line contains three correct expressions for the energy density of a magnetic field in an isotropic magnet

(is the relative magnetic permeability, 0 is the magnetic constant, is the value of the magnetic induction vector, is the value of the vector of the magnetic field)? = , = , = .

4. The magnetic flux penetrating the coil changes over time according to a graph. In what interval is the induction emf equal to zero? − .

5. Which statement regarding the properties of conduction currents and cohesion currents is correct? Both currents create a magnetic field.

6. An electron moves in a circle in a uniform magnetic field with a strength of 10 kA/m. Calculate the rotation period of the electron. The specific charge of an electron is considered equal to 1.8*10 11 C/kg, magnetic constant0 = 4 10−7 H/m.l =c ;l =

= ; = ; c = ; = ; = ; = ; =										= . − p.

1. The currents in two parallel conductors are equal in magnitude and directed in opposite directions. Determine the direction of the resulting magnetic induction vector at point A. Up.

2. Compare the circulations of the magnetic field strength vector of an infinite direct current, perpendicular to the plane of the figure, along a closed contour in four cases. ==; = .

3. Choose the correct relation for the directions of the vectors of intensity, magnetic induction and magnetization in a homogeneous isotropic diamagnet. and are directed in the same direction, in the opposite direction.

4. A closed conductor is in a uniform magnetic field directed beyond the drawing. The induction decreases with time. Determine the direction of the induction current in the conductor. Clockwise.

5. Two protons with different energies fly into a uniform magnetic field. Which trajectory of motion corresponds to the proton with the highest energy? Trajectory 2.

6. A capacitor with a capacitance of 2 μF is included in the oscillatory circuit. What is the total energy stored in

		if the charge of the capacitor (in C) changes according to the law = 0.02 sin(12345)? =

1. Select the line in which the physical quantities have the dimension of A/m (- intensity

magnetic field, is the magnetic permeability, is the magnetization of the magnet, is the current density, is the magnetic moment). , .

2. Compare the units of magnetic field induction at the center of the coil with the current for the three conductor configurations. > > .

4. Do tungsten (= 1.000176), platinum (= 1.000360) and bismuth (= 0.999524) substances belong to paramagnets? Only tungsten and platinum are included.

5. The following system of Maxwell equations

valid ... only in the absence of conduction currents.

6. A 500nF capacitor is connected in parallel with a 1mH inductor. Determine the oscillation period of the oscillator. = √ = √− − = .− с = . ms.

1. The circulation of the magnetic field strength vector is equal to zero ... then, if the circuit does not cover currents.

2. In Boris Leonidovich Pasternak's poem "Explanation" there is such a stanza. What arrangements of two direct currents does the author speak about? A variant where the currents are co-directed and parallel to each other.

3. Properties of the magnetic field strength of an infinite solenoid (- solenoid current). Inside the solenoid, the field is uniform and = (is the number of turns per unit length of the solenoid). Outside the solenoid, the field is zero.

4. A proton and a particle (= 2 ; = 4) accelerate to the same energy and fly into the magnetic field at different angles of 30° and 60°, respectively, to the direction of the magnetic induction vector. How are the periods of revolution of a proton related?

(1) and particles (2)? = .

5. At the exam testing in physics, a first-year student at NRU ITMO provided the following Maxwell equations in integral form. Did he make a mistake in them, and if so, in what equation. Look at the application. If all coincided with the equations of the complete system, then the answer is “no error”.

6. The equation of damped oscillations has the form′′ + 0.5′ + 900 = 0.1 cos 150. The damping coefficient is much less than the natural oscillation frequency. How much should the frequency of the driving force be reduced in order for resonance to occur? From

	the equation follows that = ;	= ; = . ;

1. How is the circuit with current located when it is freely oriented in a uniform magnetic field? The normal to the contour is parallel to the magnetic induction vector.

2. The value of the magnetic induction vector in the center of a circular conductor with a radius and current strength is ... .

3. The circulation of the magnetic field strength vector during a bypass along a circuit penetrating current-carrying conductors is equal to ... the algebraic sum of the currents penetrating the circuit.

4. is the magnetic susceptibility of paramagnets, is the magnetic moment of their atoms. Which statement is correct? > , | | , ≠ .

5. Two electrons with different energies fly into a uniform magnetic field. Which trajectory of motion corresponds to the electron with the lowest energy? Trajectory 5.

6. Oscillation of a material point with a mass of 0.1 g occurs according to the equation = cos , where = 5cm, = 20s-1 . Define

the maximum value of the restoring force. = = − ; max = = . . = . N.

1. The unit of measurement of the mutual induction coefficient is ... Henry.

2. The value of the vector of magnetic induction of the field of infinite direct current depends on the distance between the observation point and the conductor with current as follows ....

3. The elementary work of the Ampere force when moving a circuit with current in a magnetic field is equal to the product of the current strength in the circuit ... and the change in the magnetic flux penetrating the circuit. For a = ∫.

4. The magnetic flux penetrating the coil changes over time in accordance with the graph. In what time interval does the induction EMF have a minimum value in absolute value, but not equal to zero? − . For the EMF of induction depends on the rate of change of the flux.

5. The voltage on the capacitor in the oscillatory circuit is described by the expression = 0 (2 ). AT

at what point in time is the magnetic field energy in the coil maximum (- period)? = .

6. A point charge flies at a speed of 15 m/s into a uniform magnetic field with an induction of 2T. The velocity and magnetic induction vectors form an angle of 30°. Find the magnitude of the charge if the Lorentz force acting on the particle from the side of the field is equal to

1. Indicate the line that correctly represents the Biot-Savart-Laplace law and the rule that should be followed when determining the direction of the magnetic induction of a current element. =[× ] , right screw rule.

2. Choose the correct expression for the magnetization vector. – .

3. A conductor moves in a uniform magnetic field. The potential of which of the two points of the conductor (s) is higher? The potentials are the same.

4. At the exam testing in physics, a student 1st year NRU ITMO presented the following Maxwell equations in integral form. Did he make a mistake in them, and if so, in what equation? = ∫ .

5. The total energy of a mechanical oscillator oscillating according to the law = sin ... is proportional.

6. A 500pF capacitor is connected in parallel with a 1mH inductor Determine the period of oscillation

oscillator. = √ = √ − − = .− s.

1. Properties of magnetic field lines (lines of magnetic induction). The lines are arranged so that the tangents to these lines would coincide in direction with the magnetic induction vector.

2. An infinitely long rectilinear current-carrying conductor passes along the axis of a circular current-carrying circuit. How does the magnetic field of a conductor act on a circular circuit? Doesn't work at all.

3. The magnetic susceptibility is less than zero in the case of...only diamagnets.

4. A closed conductor is in a uniform magnetic field. The induction increases with time. Determine the direction of the induction current in the conductor. If the current is directed away from the observer, then clockwise. If on - counterclockwise.

5. What type of energy does an ideal oscillatory circuit contain half a period after the start of the capacitor discharge? Only electric.

6. Flat contour area 250cm 2 is in a uniform magnetic field with an induction of 0.2 T. Find the magnetic flux

if its plane makes an angle of 30 degrees with the lines of induction. F = ; F = = , = , Wb.

1. The unit of measure for the mutual induction coefficient is…Henry.

2. In an isotropic magnet with permeability, the magnetic induction is equal. Choose the correct expression for the magnetic field strength. .

3. What number correctly represents the expressions related to the inductance of the circuit. (- full magnetic

the flow penetrating the circuit, - the current strength in the circuit, - the inductive EMF that occurs in the circuit, - the magnitude of the magnetic induction)? = ; = − .

4. Which bulb in the diagram will light up the latest after the key is closed? 3. Inductance will interfere with current flow.

5. How will the frequency of electromagnetic oscillations change if a ferrimagnetic core is introduced into the inductor? will increase.

6. An electron moves in a circle in a uniform magnetic field with a strength of 10 kA/m. Calculate rotation period

magnetic constant

4 10−7 H/m.

c ;l = = ; = ;c = ; = ; = ; = ; =

− p.

For reference on assignments for Maxwell's equations: The complete system, taking into account everything that is possible:

AT in the absence of charged bodies changes:

AT the absence of conduction currents changes:

Guys, I won’t pass these tasks, the only 3 will come out! Help) 1. What is the resistance of 1 m of constantan wire with a diameter of 0.8 mm? 2.When

coil winding copper wire her mass increased by 17.8 d,a resistance turned out to be 34 Ohm. Estimate the length and cross-sectional area of ​​\u200b\u200bthe wire from these data?

3. An ammeter and a resistor with a resistance of 2 ohms were connected in series to a current source with an internal resistance of 1 ohm. At the same time, the ammeter showed 1 A. What will the ammeter show if a 3 ohm resistor is used?

4. In the circuit, the voltmeter shows 3V, and the ammeter 0.5 A. With a current of 1A, the voltmeter shows 2.5 V. What are the EMF and internal resistance of the source?

5. A force of 6N acts on a charge of 3C in an electrostatic field. What is the field strength?

a.18 n/k b.0.5 n/k c.2n/k d 24 n/k e.there are no correct answers

6. How will the strength of the electric field of a point charge transferred from vacuum to a medium with a dielectric constant equal to 81 change?

a. will increase by 9 times b. will decrease by 9 times c. will increase in 81 d. will decrease by 81 times e. will not change

10. When moving an electric charge between points with a potential difference of 8 V, the forces acting on the charge from the electric field did the work of 4 J. What is the magnitude of the charge?

a.4 class b.32 class c.0.5 class d.2 class e.no correct

11. Charge 2cl moves from a point with a potential of 10 V to a point with a potential of 15 V. What work does the electric field do in this case?

a.10 j b.-10 j c.0.4 j d.2.5 j e. no correct

12. When a charge of 3 cells moves from 1 point to another, the electric field does 6 J of work. What is the potential difference between these points?

a.18 C b.2C c.0.5C d.9 E. no correct

13. How will the capacitance of a capacitor change when a dielectric with a permittivity of 2 is removed from it?

1) How will the force of the Coulomb interaction of two small charged balls change with an increase in the charge of each of them by 2 times, if the distance between

balls remains unchanged?

A. Will increase by 2 times. B. Will not change. B. Will increase by 4 times. D. Decrease by 2 times.

D. Decrease by 4 times.

2) What carriers of electric charge create electricity in metals?

A. Electrons and positive ions. B. Positive and negative ions. B. Positive, negative ions and electrons D. Only electrons. E. Among the answers A - D, there is no correct one.

3) The heat engine receives 100 J of heat from the heater per cycle and gives 60 J to the refrigerator. What is the efficiency of the machine?

A. 67%. B. 60%. B. 40%. D. 25%. E. Among the answers A - D, there is no correct one.

4) How will the pressure of an ideal gas change with an increase in the concentration of its molecules by a factor of 3, if the mean square velocity of the molecules remains unchanged?

A. It will increase 9 times. B. Will increase by 3 times. B. Will remain unchanged. D. Decrease by 3 times. D. Decrease by 9 times.

5) How will the average kinetic energy thermal motion of molecules of an ideal gas with an increase in the absolute temperature of the gas by a factor of 3?

A. It will increase by 3 times. B. Will increase by 2 times. B. Will increase by 4.5 times. D. Will increase 9 times.
6) Estimate the approximate mass of air with a volume of 1 m3 at normal atmospheric pressure and a temperature of 300 K. From the values ​​below, choose the one closest to your result.

A. 1 g. B. 10 g. C. 100 g. D. 1 kg. D. 10 kg.

Physical dictation

“Electrification of tel. The law of conservation of electric charge "

1. What is the name of the section of physics that studies charged bodies?

2. What interaction exists between charged bodies, particles?

3. What physical quantity determines the electromagnetic interaction?

4. Does the magnitude of the charge depend on the choice of reference system?

5. Is it possible to say that the charge of the system is the sum of the charges of the bodies included in this system?

6. What is the name of the process leading to the appearance of electric charges on bodies?

7. If the body is electrically neutral, does this mean that it does not contain electric charges?

8. Is it true that in a closed system the algebraic sum of the charges of all the bodies of the system remains constant?

9. If the number of charged particles in a closed system has decreased, does this mean that the charge of the entire system has also decreased?

_____________________________________________________________________________

Physical dictation

“The law of conservation of electric charge. Coulomb's law.

1. Can you create an electric charge?

2. Do we create an electric charge during electrification?

3. Can charge exist independently of particles?

4. The body, the total positive charge of the particles of which is equal to the total negative charge of the particles, is ...

5. The strength of the interaction of infected particles with an increase in the charge of any of these particles?

6. When placing charges in a medium, the force of interaction between them ...

7. With an increase in the distance between charges by 3 times, the interaction force ...

8. The quantity characterizing the electrical properties of the medium is called ...

9. In what units is the electric charge measured?

Physical dictation “Electrification of bodies.

The law of conservation of electric charge. Coulomb's law.

Capacitors
1. The ability of a conductor to accumulate charge is called ...
2. In what units is the electrical capacity measured?
3. What is the name of a system of two conductors separated by a dielectric layer?
4. What is meant by the charge of a capacitor?
5. Where is the electric field of the capacitor concentrated?
6. How will the capacitance of the capacitor change if a dielectric is introduced between the plates?
7. Does the capacitance of the capacitor depend on the geometric dimensions?

Answers
1. … electrical capacity
2. In farads
3. Capacitor
4. Charge module of one of the plates
5. Inside, between the plates
6. Increase
7. Yes

• Can you create an electric charge?
• Do we create an electric charge when we electrify?
• Can a charge exist independently of a particle?
• A body, the total positive charge of the particles of which is equal to the total negative charge of the particles, is ...
• The strength of the interaction of charged particles with an increase in the charge of any of these particles ...
• When charges are placed in a medium, the force of interaction between them ...

• With an increase in the distance between the charges by 3 times, the interaction force ...
• The quantity characterizing the electrical properties of the medium is called ...
• What is the unit of measure for electric charge?
• What physical quantity determines the electromagnetic interaction?
• What is the name of the process that leads to the appearance of electric charges on the bodies?
• Is it true that in a closed system the algebraic sum of the charges of all the bodies of the system remains constant?

• Answers
• neutral
• is increasing
• Decreases
• Decreases by 9 times
• Dielectric Constant
• in pendants
• Electric charge
• Electrification

• Electric field

• What types of matter do you know?
• What is the name of the field of fixed charges?
• What is the source of the electric field?
• The main property of any electric field?
• What is the name of the force with which the charges interact?
• What is the name of the physical quantity equal to the ratio of the force acting on the charge from the electric field to this charge?

• Write down the formula for the strength of the electric field, a point charge.
• In what units is the electric field strength measured?
• How will the intensity change with increasing electric charge?
• How will the intensity change as the distance from the point to the charge increases?
• How will the force acting on the charge change if the electric field strength is doubled?
• What charge is placed in an electric field if the vector of the force acting on the charge coincides with the vector of intensity in direction?

• Answers
• Substance, field
• electrostatic
• Charge
• Action on electric charges
• Kulonovskaya
• Electric field strength
• E = kq/r2
• N/cl = V/m
• will increase
• will decrease
• Will increase by 2 times
• Positive

• The work of the forces of the electrostatic field. Potential difference

• If the work of the field forces along any closed trajectory is zero, then the field is called...?
• On what quantities does the work of electric field forces depend?
• Does the work of the electric field forces depend on the shape of the trajectory?
• What is the energy characteristic of the electric field?
• In what units is it measured?
• Does the value of the potential depend on the choice of the zero level?
• Express the volt in terms of other units.

• What is the work of the electric field forces when the charge moves perpendicular to the field lines of force?
• When finding the common potential of several electric fields, all potentials ...
• What is the work of the Coulomb forces on a closed path?
• What is voltage in electrostatics?
• How is voltage measured?
• What are surfaces of equal potential called?
• How are voltage and intensity related in a uniform electrostatic field?

• Answers
• Potential
• From charge, tension, distance
• Potential
• in volts
• J/C
• Algebraically add up
• Potential difference
• Volt
• equipotential
• U = E d

• "Spectra"

• 1. Light sources are...
• A. Atoms.
• B. Molecules.
• B. Atoms and molecules.
• 2. A spectrum in which the width of the color bands is approximately the same is called ...
• A. Prismatic. B. Diffractive.
• B. Solid.
• 3. The spectrum, which contains a certain set of wavelengths, is called ...
• A. Solid. B. Ruled.
• B. Striped.
• 4. The spectrum in which all wavelengths are represented is called ...
• A. Solid. B. - Ruled.
• B. Striped.
• 5. The spectrum, in which the spectral lines are combined into groups separated by dark gaps, is called ...
• A. Solid. B. Ruled.
• B. Striped.

• 6. What spectrum does hot metal give?
• A. Solid. B. Ruled.
• B. Striped.
• 7. Bodies consisting of excited molecules that do not interact with each other give spectra ...
• A. Solid. B. Ruled.
• B. Striped.
• 8. What spectrum can be observed with a spectroscope from an incandescent spiral of a light bulb?
• A. Solid. B. Ruled.
• B. Striped.
• 9. Atom of each element:
• A. It emits and absorbs an arbitrary set of wavelengths. B. It emits and absorbs a specific set of wavelengths.
• B. It emits an arbitrary, but absorbs a certain set of wavelengths.
• 10. What is the difference between the line emission spectra of various chemical elements?
• A. Number of lines.
• B. The number and arrangement of lines.
• B. The number, location and color of the lines.

• 11. According to the Kirchhoff spectral law, the atoms of each chemical element absorb only those rays that ...
• A. They themselves radiate.
• B. Have a frequency greater than they themselves radiate.
• B. Have a frequency less than they themselves radiate.
• 12. Which rays are deflected by the prism more strongly:
• A. Red. B. Greens.
• B. Violet.
• 13. Which rays are deflected by the diffraction grating more strongly:
• A. Red. B. Greens.
• B. Violet.
• 14. In what state of aggregation do spectral analysis laboratories examine any substance to determine its chemical composition?
• A. In solid. B. In liquid.
• B. In a gaseous state.
• 15. What spectra are used for spectral analysis:
• A. By solid. B. Linear.
• B. By any.

• 16. What chemical element was discovered thanks to spectral analysis?
• A. Neon. B. Helium.
• B. Hydrogen.
• 17. A device for observing the visible part of the spectrum is called ...
• A. Spectrograph. B. Spectroscope.
• B. Spectrometer.
• 18. The state of atoms corresponding to all permitted energy levels, except for the lowest, is called ...
• A. Excited.
• B. Unexcited.
• B. Stationary.
• 19. An electron associated with an atom, when moving from an orbit more distant to less distant from the nucleus at the moment of transition ...
• A. Emits energy. B. Absorbs energy.
• B. Emits and absorbs energy.
• 20. An electron in a hydrogen atom has moved from the first energy level to the third. How does this change the energy of the atom?
• A. Decreased. B. Increased.
• B. Has not changed.

• Answers

• 10 - 13 mark "3"
• 14 - 17 mark "4"
• 18 - 20 rating "5"