50278 + Interview Questions in Physics

1.	A wire elongates by 1.0 mm when a load W is hanged from it. If this wire goes over a pulley and two weights W each are hung at the two ends, the elongation of the wire will be
Answer» A wire elongates by 1.0 mm when a load W is hanged from it. If this wire goes over a pulley and two weights W each are hung at the two ends, the elongation of the wire will be

Discussion

2.	A wooden plank of length 1 m and uniform cross-section is hinged at one end to the bottom of a tank as shown in figure. The tank is filled with water upto a height 0.5 m. The specific gravity of the plank is 0.5. Find the angle θ that the plank makes with the vertical in the equilibrium position. (Exclude the case θ=0∘)
Answer» A wooden plank of length $1 m$ and uniform cross-section is hinged at one end to the bottom of a tank as shown in figure. The tank is filled with water upto a height $0.5 m$ . The specific gravity of the plank is $0.5$ . Find the angle $θ$ that the plank makes with the vertical in the equilibrium position. (Exclude the case $θ = 0^{\circ})$

Discussion

3.	The gravitational field in a region is given by −→Eg=(4^i+^j) N/kg. Work done by this field will be zero when the particle is moved along the line
Answer» The gravitational field in a region is given by $_{g} = (4^i +^j) N/kg$ . Work done by this field will be zero when the particle is moved along the line

Discussion

4.	A given compound in liquid state has a vapor pressure of 190 torr at 27∘C and 1 atm at 127∘C.Calculate ΔHvap for the compoundGiven ln(2)=0.693
Answer» A given compound in liquid state has a vapor pressure of $190 t o r r$ at $27^{\circ} C$ and $1 a t m$ at $127^{\circ} C$ . Calculate $Δ H_{v a p}$ for the compound Given $ln (2) = 0.693$

Discussion

5.	In the amplifier circuit shown below, The value of the voltage gain \|V0Vs\| is equal to _____.(Assume VT=25mV and β is very large ) 150
Answer» In the amplifier circuit shown below, The value of the voltage gain $\| \frac{V_{0}}{V_{s}} \|$ is equal to _____. (Assume $V_{T} = 25 m V$ and $β$ is very large ) 150

Discussion

6.	A particle of mass 1 mg has the same de-Broglie wavelength as that of an electron moving with a velocity of 3×106 ms−1. The velocity of the particle is, [ Take mass of electron, me=9.1×10−31 kg ]
Answer» A particle of mass $1 mg$ has the same de-Broglie wavelength as that of an electron moving with a velocity of $3 \times 10^{6} {ms}^{- 1}$ . The velocity of the particle is, $[$ Take mass of electron, $m_{e} = 9.1 \times 10^{- 31} kg]$

Discussion

7.	A cart is pulled with a constant force F with a constant velocity v = 3m/s on a smooth horizontal ground. A hopper loads the cart with sands at a rate of 2 kg/s. (a) Explain why, even though there is a net external force on the cart, the cart experiences no acceleration and moves with constant velocity(b)Find the rate of loss of mechanical energy.
Answer» A cart is pulled with a constant force F with a constant velocity v = 3m/s on a smooth horizontal ground. A hopper loads the cart with sands at a rate of 2 kg/s. (a) Explain why, even though there is a net external force on the cart, the cart experiences no acceleration and moves with constant velocity (b)Find the rate of loss of mechanical energy.

Discussion

8.	(a+b+c+d)*4
Answer» (a+b+c+d)*4

Discussion

9.	a rod of length 2m rests on a smooth horizontal floor. If the rod is heated from 0 degree celsius to 20 degree celsius. Find the longitudinal strain developed?
Answer» a rod of length 2m rests on a smooth horizontal floor. If the rod is heated from 0 degree celsius to 20 degree celsius. Find the longitudinal strain developed?

Discussion

10.	Is average value of ac same as dc for every sinusoidal wave function.
Answer» Is average value of ac same as dc for every sinusoidal wave function.

Discussion

11.	A wire of mass m and length l can slide freely on a pair of smooth, vertical rails (figure 38-E31). A magnetic field B exists in the region in the direction perpendicular to the plane of the rails. The rails are connected at the top end by a capacitor of capacitance C. Find the acceleration of the wire neglecting any electric resistance.
Answer» A wire of mass m and length l can slide freely on a pair of smooth, vertical rails (figure 38-E31). A magnetic field B exists in the region in the direction perpendicular to the plane of the rails. The rails are connected at the top end by a capacitor of capacitance C. Find the acceleration of the wire neglecting any electric resistance.

11.

A wire of mass m and length l can slide freely on a pair of smooth, vertical rails (figure 38-E31). A magnetic field B exists in the region in the direction perpendicular to the plane of the rails. The rails are connected at the top end by a capacitor of capacitance C. Find the acceleration of the wire neglecting any electric resistance.

Answer»

A wire of mass m and length l can slide freely on a pair of smooth, vertical rails (figure 38-E31). A magnetic field B exists in the region in the direction perpendicular to the plane of the rails. The rails are connected at the top end by a capacitor of capacitance C. Find the acceleration of the wire neglecting any electric resistance.

Discussion

12.	What is the radius of the path of an electron (mass 9×10^-31 kg and charge 1.6×10^-19) moving at a speed of 3×10^7 m/s in a magnetic field of 6×10^-4 T perpendicukar to it? What is the frequency? Calculate its enegy in keV. (1 keV=1.6×10^-19 J).
Answer» What is the radius of the path of an electron (mass 9×10^-31 kg and charge 1.6×10^-19) moving at a speed of 3×10^7 m/s in a magnetic field of 6×10^-4 T perpendicukar to it? What is the frequency? Calculate its enegy in keV. (1 keV=1.6×10^-19 J).

Discussion

13.	Figure shows three forces applied to a block that moves leftwards by 3 m over a smooth floor. The magnitudes of forces are F1=3 N,F2=9 N, and F3=5 N. The net work done on the block by the three forces is
Answer» Figure shows three forces applied to a block that moves leftwards by $3 m$ over a smooth floor. The magnitudes of forces are $F_{1} = 3 N, F_{2} = 9 N$ , and $F_{3} = 5 N$ . The net work done on the block by the three forces is

Discussion

14.	32.an aeroplane of mass 1000 kg is flying in circular path of radius 1000m with a speed of 720km/h what is force on aeroplane is
Answer» 32.an aeroplane of mass 1000 kg is flying in circular path of radius 1000m with a speed of 720km/h what is force on aeroplane is

Discussion

15.	The left block in figure (12-E13) moves at a speed v towards the right block placed in equilibrium. All collisions to take place are elastic and the surfaces are frictionless. Show that the motions of the two blocks are periodic. Find the time period of these periodic motions. Neglect the widths of the blocks.
Answer» The left block in figure (12-E13) moves at a speed v towards the right block placed in equilibrium. All collisions to take place are elastic and the surfaces are frictionless. Show that the motions of the two blocks are periodic. Find the time period of these periodic motions. Neglect the widths of the blocks.

15.

The left block in figure (12-E13) moves at a speed v towards the right block placed in equilibrium. All collisions to take place are elastic and the surfaces are frictionless. Show that the motions of the two blocks are periodic. Find the time period of these periodic motions. Neglect the widths of the blocks.

Answer»

The left block in figure (12-E13) moves at a speed v towards the right block placed in equilibrium. All collisions to take place are elastic and the surfaces are frictionless. Show that the motions of the two blocks are periodic. Find the time period of these periodic motions. Neglect the widths of the blocks.

Discussion

16.	In an AC circuit, the current is given by the equation, i=2√13sin(50πt) A. Calculate the time taken to reach from zero (at t=0) to its first maximum value.
Answer» In an AC circuit, the current is given by the equation, $i = 2 \sqrt{13} sin (50 π t) A$ . Calculate the time taken to reach from zero $($ at $t = 0)$ to its first maximum value.

Discussion

17.	Applying the momentum and energy conservation formulas,show that if K=1 then in case of the head on elastic collision between two bodies of mass M and KM the first one loses maximum energy.
Answer» Applying the momentum and energy conservation formulas,show that if K=1 then in case of the head on elastic collision between two bodies of mass M and KM the first one loses maximum energy.

Discussion

18.	how much force does a cubid of ocean water have??
Answer» how much force does a cubid of ocean water have??

Discussion

19.	why cannot we use wheatstone bridge in simplifying symmetrical circuits
Answer» why cannot we use wheatstone bridge in simplifying symmetrical circuits

Discussion

20.	If the terminal speed of a sphere of gold (density = 19.5 g/cm3) is 0.2 m/s in a viscous liquid (density = 1.5 g/cm3). Find the terminal speed of a sphere of silver (density =10.5 g/cm3) of the same size in the same liquid.
Answer» If the terminal speed of a sphere of gold (density = $19.5 {g/cm}^{3})$ is $0.2 m/s$ in a viscous liquid (density = $1.5 {g/cm}^{3}$ ). Find the terminal speed of a sphere of silver (density $= 10.5 {g/cm}^{3})$ of the same size in the same liquid.

Discussion

21.	A light of frequency 10^16Hz is irradiated on a metal surface with threshold frequency equal to 5x10^15 Hz. What would be the maximum kinetic energy of photoelectrons emitted ?(1)3.313x10^-15J(2)3.313x10^-18J(3)1.02x10^16J(4)4.316x10^-18J
Answer» A light of frequency 10^16Hz is irradiated on a metal surface with threshold frequency equal to 5x10^15 Hz. What would be the maximum kinetic energy of photoelectrons emitted ? (1)3.313x10^-15J (2)3.313x10^-18J (3)1.02x10^16J (4)4.316x10^-18J

Discussion

22.	For a material of poison ratio 0.20 under an external stress, if the longitudinal strain is 0.01 the percentage change in diameter of wire
Answer» For a material of poison ratio 0.20 under an external stress, if the longitudinal strain is 0.01 the percentage change in diameter of wire

Discussion

23.	Two equal forces →F are acting such that the magnitude of their resultant is equal to F. They must be inclined at an angle of __ degrees
Answer» Two equal forces $\to F$ are acting such that the magnitude of their resultant is equal to F. They must be inclined at an angle of __ degrees

Discussion

24.	fine the nature of image when an object is placed at 3f from the pole of aconvex mirror of focal length f
Answer» fine the nature of image when an object is placed at 3f from the pole of aconvex mirror of focal length f

Discussion

25.	A series LCR circuitwith R = 20 Ω, L =1.5 H and C = 35 μFis connected to a variable-frequency 200 V ac supply. When thefrequency of the supply equals the natural frequency of the circuit,what is the average power transferred to the circuit in one completecycle?
Answer» A series LCR circuit with R = 20 Ω, L = 1.5 H and C = 35 μF is connected to a variable-frequency 200 V ac supply. When the frequency of the supply equals the natural frequency of the circuit, what is the average power transferred to the circuit in one complete cycle?

Discussion

26.	31.Find the dimension of the following in terms of mass , time , length and charge ? a) Magnetic flux b) Rigidity modulus c) Emf d) potential difference e) electric potential f) Dipole moment g) Electric flux h) Electric field i) electromotive force j)light year and wavelength k) gravitational potential l) curie m) frequency of a light wave n) Reynolds number o) coefficient of friction
Answer» 31.Find the dimension of the following in terms of mass , time , length and charge ? a) Magnetic flux b) Rigidity modulus c) Emf d) potential difference e) electric potential f) Dipole moment g) Electric flux h) Electric field i) electromotive force j)light year and wavelength k) gravitational potential l) curie m) frequency of a light wave n) Reynolds number o) coefficient of friction

Discussion

27.	A particle is executing a simple harmonic motion. Its maximum acceleration is α and maximum velocity is β. Its time period of vibration will be
Answer» A particle is executing a simple harmonic motion. Its maximum acceleration is $α$ and maximum velocity is $β .$ Its time period of vibration will be

Discussion

28.	2 charges q1 and q2 are placed in vaccum at a distace d and the force acring between them if F.If a medium of dielectric constant 4 is introduce around them then the force
Answer» 2 charges q1 and q2 are placed in vaccum at a distace d and the force acring between them if F.If a medium of dielectric constant 4 is introduce around them then the force

Discussion

29.	if work done by electrostatic force on a system of point charges is positive then the potential energy of system will ?? increase or decrease
Answer» if work done by electrostatic force on a system of point charges is positive then the potential energy of system will ?? increase or decrease

Discussion

30.	The current in 2 ohm resistor shown in the figure below is
Answer» The current in 2 ohm resistor shown in the figure below is

Discussion

31.	If charge flown through a wire is given by q=3sin(3t), then find out the current flown through the wire at t=π9 seconds.
Answer» If charge flown through a wire is given by $q = 3 sin (3 t)$ , then find out the current flown through the wire at $t = \frac{π}{9}$ seconds.

Discussion

32.	Displacement per unit time is defined as ___
Answer» Displacement per unit time is defined as ___

Discussion

33.	Uniform rod AB of mass 3 kg and length 2 m is hinged at end A in horizontal position as shown in the figure. The other end is connected to a block of mass 1 kg through a massless string. The pulley is smooth and massless. Find the angular acceleration of the rod about the hinge just after release. (Take anti-clockwise rotation positive)
Answer» Uniform rod $A B$ of mass $3 kg$ and length $2 m$ is hinged at end $A$ in horizontal position as shown in the figure. The other end is connected to a block of mass $1 kg$ through a massless string. The pulley is smooth and massless. Find the angular acceleration of the rod about the hinge just after release. (Take anti-clockwise rotation positive)

Discussion

34.	The motion of a particle along a stright line is described by the equation x=8+12t−t3 where, x is in meter and t in second. The retardation of the particle when its velocity beocmes zero, is
Answer» The motion of a particle along a stright line is described by the equation $x = 8 + 12 t - t^{3}$ where, $x$ is in meter and $t$ in second. The retardation of the particle when its velocity beocmes zero, is

Discussion

35.	A circular wire loop of radius a carries a total charge −Q distributed uniformly over its length. A small length dL of the wire is cut - off at A, then the direction of electric field at the centre due to the remaining wire is along.
Answer» A circular wire loop of radius $a$ carries a total charge $- Q$ distributed uniformly over its length. A small length $d L$ of the wire is cut - off at $A$ , then the direction of electric field at the centre due to the remaining wire is along.

Discussion

36.	40.A particle of mass m is kept on the top of a smooth sphere of radius R .it is given a sharp impulse which imparts it a horizontal speed V.what should be the minimum value of v for which the particle does not slip on the sphere?(with full reason)
Answer» 40.A particle of mass m is kept on the top of a smooth sphere of radius R .it is given a sharp impulse which imparts it a horizontal speed V.what should be the minimum value of v for which the particle does not slip on the sphere?(with full reason)

Discussion

37.	A light wire of length l (figure – 1) is cut into two pieces in two different ways as shown in (figure – 2 & 3). Different pieces can be arranged in place of wire as shown and a load can be placed on the massless hanger. Choose the correct statements(s) : -
Answer» A light wire of length l (figure – 1) is cut into two pieces in two different ways as shown in (figure – 2 & 3). Different pieces can be arranged in place of wire as shown and a load can be placed on the massless hanger. Choose the correct statements(s) : -

37.

A light wire of length l (figure – 1) is cut into two pieces in two different ways as shown in (figure – 2 & 3). Different pieces can be arranged in place of wire as shown and a load can be placed on the massless hanger. Choose the correct statements(s) : -

Answer»

A light wire of length l (figure – 1) is cut into two pieces in two different ways as shown in (figure – 2 & 3). Different pieces can be arranged in place of wire as shown and a load can be placed on the massless hanger. Choose the correct statements(s) : -

Discussion

38.	(a) An X-raytube produces a continuous spectrum of radiation with its shortwavelength end at 0.45 Å. What is the maximum energy of aphoton in the radiation?(b) Fromyour answer to (a), guess what order of accelerating voltage (forelectrons) is required in such a tube?
Answer» (a) An X-ray tube produces a continuous spectrum of radiation with its short wavelength end at 0.45 Å. What is the maximum energy of a photon in the radiation? (b) From your answer to (a), guess what order of accelerating voltage (for electrons) is required in such a tube?

38.

(a) An X-raytube produces a continuous spectrum of radiation with its shortwavelength end at 0.45 Å. What is the maximum energy of aphoton in the radiation?(b) Fromyour answer to (a), guess what order of accelerating voltage (forelectrons) is required in such a tube?

Answer»

(a) An X-ray
tube produces a continuous spectrum of radiation with its short
wavelength end at 0.45 Å. What is the maximum energy of a
photon in the radiation?

(b) From
your answer to (a), guess what order of accelerating voltage (for
electrons) is required in such a tube?

Discussion

39.	what is electric displacement?
Answer» what is electric displacement?

Discussion

40.	A steel wire and a copper wire of equal length and equal cross-sectional area are joined end to end and the combination is subjected to a tension. Find the ratio of (a) the stresses developed in the two wires and (b) the strains developed. Y of steel = 2×1011Nm−2. Y of copper = 1.3×1011Nm−2.
Answer» A steel wire and a copper wire of equal length and equal cross-sectional area are joined end to end and the combination is subjected to a tension. Find the ratio of (a) the stresses developed in the two wires and (b) the strains developed. Y of steel = $2 \times 10^{11} N m^{- 2}$ . Y of copper = $1.3 \times 1011 N m^{- 2}$ .

Discussion

41.	A tennis ball hits the floor with a speed v at an angle θ with the normal to the floor. If the collision is inelastic and the coefficient of restitution is ε, what will be the angle of reflection?
Answer» A tennis ball hits the floor with a speed $v$ at an angle $θ$ with the normal to the floor. If the collision is inelastic and the coefficient of restitution is $ε$ , what will be the angle of reflection?

Discussion

42.	A force →F=(3^i+4^j) N acts on a particle moving in x−y plane. Starting from the origin, the particle first goes along x - axis to the point (4 m, 0) and then parallel to the y - axis to the point (4 m,3 m). The total work done by the force on the particle is
Answer» A force $\to F = (3^i + 4^j) N$ acts on a particle moving in $x - y$ plane. Starting from the origin, the particle first goes along $x$ - axis to the point $(4 m, 0)$ and then parallel to the $y$ - axis to the point $(4 m, 3 m)$ . The total work done by the force on the particle is

Discussion

43.	A charged particle with charge q enters a region of constant, uniform and mutually orthogonal fields →E and →B , with a velocity →v perpendicular to both →E and →B, and comes out without any change in magnitude or direction of →v. Then
Answer» A charged particle with charge $q$ enters a region of constant, uniform and mutually orthogonal fields $\to E$ and $\to B$ , with a velocity $\to v$ perpendicular to both $\to E$ and $\to B$ , and comes out without any change in magnitude or direction of $\to v$ . Then

Discussion

44.	a body of mass 4 kg initially at rest. A force acts on it for 4s and then ceases to act. The body covers 4m in 4s. Find the force acting on the body for the first four seconds and the total distance covered by it for 8s of the total journey.
Answer» a body of mass 4 kg initially at rest. A force acts on it for 4s and then ceases to act. The body covers 4m in 4s. Find the force acting on the body for the first four seconds and the total distance covered by it for 8s of the total journey.

Discussion

45.	In Young's double slit experiment, the wavelength of red light is 7800 ˚A and that of blue is 5200 ˚A. The value of n for which nth bright band due to red light coincides with (n+1)th bright band due to blue light is-
Answer» In Young's double slit experiment, the wavelength of red light is $7800 ˚ A$ and that of blue is $5200 ˚ A .$ The value of $n$ for which $n^{t h}$ bright band due to red light coincides with $(n + 1)^{t h}$ bright band due to blue light is-

Discussion

46.	A particle is moving along a circular path of radius 5m with a uniform speed 5m per second. What will be the average acceleration when the particle completes half revolution?
Answer» A particle is moving along a circular path of radius 5m with a uniform speed 5m per second. What will be the average acceleration when the particle completes half revolution?

Discussion

47.	A small square loop of wire of side l is placed inside a large square loop of side L (l<<L). The loops are co-planar and their centres coincide. The mutual induction of the system is nμ0l2√2πL. Find the value of n
Answer» A small square loop of wire of side $l$ is placed inside a large square loop of side $L (l << L) .$ The loops are co-planar and their centres coincide. The mutual induction of the system is $\frac{n μ_{0} l^{2}}{\sqrt{2} π L}$ . Find the value of $n$

Discussion

48.	A car of mass m starts from rest at time t=0 and is driven on a straight horizontal road by the engine which exerts a constant force F. If friction is negligible, the car acquires kinetic energy E at time t and develops a power P.Which of the following is/are correct?
Answer» A car of mass $m$ starts from rest at time $t = 0$ and is driven on a straight horizontal road by the engine which exerts a constant force $F$ . If friction is negligible, the car acquires kinetic energy $E$ at time $t$ and develops a power $P$ . Which of the following is/are correct?

Discussion

49.	33.A bullet of mass 0.01 kg is fired from gun of mass 0.5 kg. If intial velocity of the bullet is250 m/sec then gun recoil at the velocity of
Answer» 33.A bullet of mass 0.01 kg is fired from gun of mass 0.5 kg. If intial velocity of the bullet is250 m/sec then gun recoil at the velocity of

Discussion

50.	A paramagnetic substance, in the form of a cube with sides 1 cm, has a magnetic dipole moment of 20×10−6 J/T, when a magnetic intensity of 60×103 A/m is applied. Its magnetic susceptibility is :
Answer» A paramagnetic substance, in the form of a cube with sides $1 cm$ , has a magnetic dipole moment of $20 \times 10^{- 6} J/T$ , when a magnetic intensity of $60 \times 10^{3} A/m$ is applied. Its magnetic susceptibility is :

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

A wire elongates by 1.0 mm when a load W is hanged from it. If this wire goes over a pulley and two weights W each are hung at the two ends, the elongation of the wire will be

The gravitational field in a region is given by −→Eg=(4^i+^j) N/kg. Work done by this field will be zero when the particle is moved along the line

A given compound in liquid state has a vapor pressure of 190 torr at 27∘C and 1 atm at 127∘C.Calculate ΔHvap for the compoundGiven ln(2)=0.693

In the amplifier circuit shown below, The value of the voltage gain |V0Vs| is equal to _____.(Assume VT=25mV and β is very large ) 150

A particle of mass 1 mg has the same de-Broglie wavelength as that of an electron moving with a velocity of 3×106 ms−1. The velocity of the particle is, [ Take mass of electron, me=9.1×10−31 kg ]

(a+b+c+d)*4

a rod of length 2m rests on a smooth horizontal floor. If the rod is heated from 0 degree celsius to 20 degree celsius. Find the longitudinal strain developed?

Is average value of ac same as dc for every sinusoidal wave function.

What is the radius of the path of an electron (mass 9×10^-31 kg and charge 1.6×10^-19) moving at a speed of 3×10^7 m/s in a magnetic field of 6×10^-4 T perpendicukar to it? What is the frequency? Calculate its enegy in keV. (1 keV=1.6×10^-19 J).

Figure shows three forces applied to a block that moves leftwards by 3 m over a smooth floor. The magnitudes of forces are F1=3 N,F2=9 N, and F3=5 N. The net work done on the block by the three forces is

32.an aeroplane of mass 1000 kg is flying in circular path of radius 1000m with a speed of 720km/h what is force on aeroplane is

In an AC circuit, the current is given by the equation, i=2√13sin(50πt) A. Calculate the time taken to reach from zero (at t=0) to its first maximum value.

Applying the momentum and energy conservation formulas,show that if K=1 then in case of the head on elastic collision between two bodies of mass M and KM the first one loses maximum energy.

how much force does a cubid of ocean water have??

why cannot we use wheatstone bridge in simplifying symmetrical circuits

If the terminal speed of a sphere of gold (density = 19.5 g/cm3) is 0.2 m/s in a viscous liquid (density = 1.5 g/cm3). Find the terminal speed of a sphere of silver (density =10.5 g/cm3) of the same size in the same liquid.

A light of frequency 10^16Hz is irradiated on a metal surface with threshold frequency equal to 5x10^15 Hz. What would be the maximum kinetic energy of photoelectrons emitted ?(1)3.313x10^-15J(2)3.313x10^-18J(3)1.02x10^16J(4)4.316x10^-18J

For a material of poison ratio 0.20 under an external stress, if the longitudinal strain is 0.01 the percentage change in diameter of wire

Two equal forces →F are acting such that the magnitude of their resultant is equal to F. They must be inclined at an angle of __ degrees

fine the nature of image when an object is placed at 3f from the pole of aconvex mirror of focal length f

A series LCR circuitwith R = 20 Ω, L =1.5 H and C = 35 μFis connected to a variable-frequency 200 V ac supply. When thefrequency of the supply equals the natural frequency of the circuit,what is the average power transferred to the circuit in one completecycle?

A particle is executing a simple harmonic motion. Its maximum acceleration is α and maximum velocity is β. Its time period of vibration will be

2 charges q1 and q2 are placed in vaccum at a distace d and the force acring between them if F.If a medium of dielectric constant 4 is introduce around them then the force

if work done by electrostatic force on a system of point charges is positive then the potential energy of system will ?? increase or decrease

The current in 2 ohm resistor shown in the figure below is

If charge flown through a wire is given by q=3sin(3t), then find out the current flown through the wire at t=π9 seconds.

Displacement per unit time is defined as ___

The motion of a particle along a stright line is described by the equation x=8+12t−t3 where, x is in meter and t in second. The retardation of the particle when its velocity beocmes zero, is

A circular wire loop of radius a carries a total charge −Q distributed uniformly over its length. A small length dL of the wire is cut - off at A, then the direction of electric field at the centre due to the remaining wire is along.

40.A particle of mass m is kept on the top of a smooth sphere of radius R .it is given a sharp impulse which imparts it a horizontal speed V.what should be the minimum value of v for which the particle does not slip on the sphere?(with full reason)

A light wire of length l (figure – 1) is cut into two pieces in two different ways as shown in (figure – 2 &amp; 3). Different pieces can be arranged in place of wire as shown and a load can be placed on the massless hanger. Choose the correct statements(s) : -

(a) An X-raytube produces a continuous spectrum of radiation with its shortwavelength end at 0.45 Å. What is the maximum energy of aphoton in the radiation?(b) Fromyour answer to (a), guess what order of accelerating voltage (forelectrons) is required in such a tube?

what is electric displacement?

A steel wire and a copper wire of equal length and equal cross-sectional area are joined end to end and the combination is subjected to a tension. Find the ratio of (a) the stresses developed in the two wires and (b) the strains developed. Y of steel = 2×1011Nm−2. Y of copper = 1.3×1011Nm−2.

A tennis ball hits the floor with a speed v at an angle θ with the normal to the floor. If the collision is inelastic and the coefficient of restitution is ε, what will be the angle of reflection?

A force →F=(3^i+4^j) N acts on a particle moving in x−y plane. Starting from the origin, the particle first goes along x - axis to the point (4 m, 0) and then parallel to the y - axis to the point (4 m,3 m). The total work done by the force on the particle is

A charged particle with charge q enters a region of constant, uniform and mutually orthogonal fields →E and →B , with a velocity →v perpendicular to both →E and →B, and comes out without any change in magnitude or direction of →v. Then

a body of mass 4 kg initially at rest. A force acts on it for 4s and then ceases to act. The body covers 4m in 4s. Find the force acting on the body for the first four seconds and the total distance covered by it for 8s of the total journey.

In Young's double slit experiment, the wavelength of red light is 7800 ˚A and that of blue is 5200 ˚A. The value of n for which nth bright band due to red light coincides with (n+1)th bright band due to blue light is-

A particle is moving along a circular path of radius 5m with a uniform speed 5m per second. What will be the average acceleration when the particle completes half revolution?

A small square loop of wire of side l is placed inside a large square loop of side L (l&lt;&lt;L). The loops are co-planar and their centres coincide. The mutual induction of the system is nμ0l2√2πL. Find the value of n

A car of mass m starts from rest at time t=0 and is driven on a straight horizontal road by the engine which exerts a constant force F. If friction is negligible, the car acquires kinetic energy E at time t and develops a power P.Which of the following is/are correct?

33.A bullet of mass 0.01 kg is fired from gun of mass 0.5 kg. If intial velocity of the bullet is250 m/sec then gun recoil at the velocity of

A paramagnetic substance, in the form of a cube with sides 1 cm, has a magnetic dipole moment of 20×10−6 J/T, when a magnetic intensity of 60×103 A/m is applied. Its magnetic susceptibility is :

A light wire of length l (figure – 1) is cut into two pieces in two different ways as shown in (figure – 2 & 3). Different pieces can be arranged in place of wire as shown and a load can be placed on the massless hanger. Choose the correct statements(s) : -

A small square loop of wire of side l is placed inside a large square loop of side L (l<<L). The loops are co-planar and their centres coincide. The mutual induction of the system is nμ0l2√2πL. Find the value of n