50278 + Interview Questions in Physics

1.	In the arrangement shown in figure, coefficient of friction between the two blocks is μ=12. The force of friction acting between the two blocks is
Answer» In the arrangement shown in figure, coefficient of friction between the two blocks is $μ = \frac{1}{2}$ . The force of friction acting between the two blocks is

Discussion

2.	Two stones are thrown up simultaneously from the edge of a cliff 240 m high with an initial speed of 10 m/s and 40 m/s respectively. Which of the following graph best represents the time variation of relative position of the second stone with respect to the first? (Assume stones do not rebound after hitting the ground and neglect air resistance).
Answer» Two stones are thrown up simultaneously from the edge of a cliff 240 m high with an initial speed of 10 m/s and 40 m/s respectively. Which of the following graph best represents the time variation of relative position of the second stone with respect to the first? (Assume stones do not rebound after hitting the ground and neglect air resistance).

Discussion

3.	A hoop of radius 2 m weighs 100 kg. It rolls along a horizontal floor so that its centre of mass has a speed of 20 cm/s. How much work has to be done to stop it?
Answer» A hoop of radius 2 m weighs 100 kg. It rolls along a horizontal floor so that its centre of mass has a speed of 20 cm/s. How much work has to be done to stop it?

Discussion

4.	The displacement – time graph of a body of mass 2 kg is shown. Find the impulse acting on the body in the time interval t=2 sec to t=6 sec
Answer» The displacement – time graph of a body of mass $2 kg$ is shown. Find the impulse acting on the body in the time interval $t = 2 sec$ to $t = 6 sec$

Discussion

5.	I am unable to do numericals of neet papers thermodynamics and thermal properties of matter Especially the graphs too.
Answer» I am unable to do numericals of neet papers thermodynamics and thermal properties of matter Especially the graphs too.

5.

I am unable to do numericals of neet papers thermodynamics and thermal properties of matter Especially the graphs too.

Answer»

I am unable to do numericals of neet papers thermodynamics and thermal properties of matter

Especially the graphs too.

Discussion

6.	A gas is filled in a vessel at 27C . To what temperature should it be heated in order that 1/3rd of the gas may escape out of the vessel ?
Answer» A gas is filled in a vessel at 27C . To what temperature should it be heated in order that 1/3rd of the gas may escape out of the vessel ?

Discussion

7.	C,Si, and Ge have the same lattice structure. Why is C insulator while Si and Ge intrinsic semiconductors?
Answer» $C, S i$ , and $G e$ have the same lattice structure. Why is $C$ insulator while $S i$ and $G e$ intrinsic semiconductors?

Discussion

8.	Light of wavelength λ strikes a photo-sensitive surface and electrons are ejected with kinetic energy E. If the kinetic energy is to be increased to 2E, the wavelength must be changed to λ′ where
Answer» Light of wavelength $λ$ strikes a photo-sensitive surface and electrons are ejected with kinetic energy E. If the kinetic energy is to be increased to 2E, the wavelength must be changed to $λ^{'}$ where

Discussion

9.	Acceptor circuit is
Answer» Acceptor circuit is

Discussion

10.	The pressure of a gas changes linearly with volume from 10 kPa, 200 cc to 50 kPa. 50 cc. (a) Calculate the work done by the gas. (b) If no heat is supplied or extracted from the gas, what is the change in the internal energy of the gas ?
Answer» The pressure of a gas changes linearly with volume from 10 kPa, 200 cc to 50 kPa. 50 cc. (a) Calculate the work done by the gas. (b) If no heat is supplied or extracted from the gas, what is the change in the internal energy of the gas ?

10.

The pressure of a gas changes linearly with volume from 10 kPa, 200 cc to 50 kPa. 50 cc. (a) Calculate the work done by the gas. (b) If no heat is supplied or extracted from the gas, what is the change in the internal energy of the gas ?

Answer»

The pressure of a gas changes linearly with volume from 10 kPa, 200 cc to 50 kPa. 50 cc.

(a) Calculate the work done by the gas.

(b) If no heat is supplied or extracted from the gas, what is the change in the internal energy of the gas ?

Discussion

11.	What is the total distance travelled till 30 seconds?
Answer» What is the total distance travelled till 30 seconds?

11.

What is the total distance travelled till 30 seconds?

Answer»

What is the total distance travelled till 30 seconds?

Discussion

12.	A bob of mass 10 kg is attached to wire 0.3 m long. Its breaking stress is 4.8×107N/m2. The area of cross section of the wire is 10−6m2. The maximum angular velocity with which it can be rotated in a horizontal circle
Answer» A bob of mass 10 kg is attached to wire 0.3 m long. Its breaking stress is $4.8 \times 10^{7} N / m 2$ . The area of cross section of the wire is $10^{- 6} m^{2}$ . The maximum angular velocity with which it can be rotated in a horizontal circle

Discussion

13.	Find the centre of mass of a uniform L shaped lamina (a thin flate plate) with dimensions as shown in figure. The mass of the lamina is 6 kg.
Answer» Find the centre of mass of a uniform $L$ shaped lamina (a thin flate plate) with dimensions as shown in figure. The mass of the lamina is $6 kg$ .

Discussion

14.	Four persons A,B,C and D at the corners of an square of side X move at a constant speed V. Each person maintains a direction towards the person at the next corner. The time, the persons take to meet each other is
Answer» Four persons $A, B, C$ and $D$ at the corners of an square of side $X$ move at a constant speed $V$ . Each person maintains a direction towards the person at the next corner. The time, the persons take to meet each other is

Discussion

15.	Given that →C=→A+→B. The magnitude of →A,→B and →C are 12, 5 and 13 units respectively. The angle between →A and →B is
Answer» Given that $\to C = \to A + \to B$ . The magnitude of $\to A, \to B$ and $\to C$ are 12, 5 and 13 units respectively. The angle between $\to A$ and $\to B$ is

Discussion

16.	A body tied with string revolves uniformly in a circle. How does the angular momentum of the body change from its initial value if the string is cut suddenly?
Answer» A body tied with string revolves uniformly in a circle. How does the angular momentum of the body change from its initial value if the string is cut suddenly?

Discussion

17.	The weight of one litre of a gas at 1atm. Pressure and 300K is 4g. At what temperature the weight of the gas is 4g when the pressure is made 0.5 atm and volume is 1 litre?
Answer» The weight of one litre of a gas at 1atm. Pressure and 300K is 4g. At what temperature the weight of the gas is 4g when the pressure is made 0.5 atm and volume is 1 litre?

Discussion

18.	Two wires P and Q of same length and material but radii in the ratio 2 : 1 are suspended from a rigid support. Find the ratio of strain produced in the wires when both are under same force.
Answer» Two wires P and Q of same length and material but radii in the ratio 2 : 1 are suspended from a rigid support. Find the ratio of strain produced in the wires when both are under same force.

Discussion

19.	(a) A rod of length 'l' is moved horizontally with a uniform velocity 'v' in a direction perpendicular to its length through a region in which a uniform magnetic field is acting vertically downward. Derive the expression for the emf induced across the ends of the rod. (b) How does one understand this motional emf by invoking the Lorentz force acting on the free charge carriers of the conductor? Explain.
Answer» (a) A rod of length 'l' is moved horizontally with a uniform velocity 'v' in a direction perpendicular to its length through a region in which a uniform magnetic field is acting vertically downward. Derive the expression for the emf induced across the ends of the rod. (b) How does one understand this motional emf by invoking the Lorentz force acting on the free charge carriers of the conductor? Explain.

Discussion

20.	The displacement time graph for two particles A and B are straight lines inclined at angles of 30∘ and 60∘ with the time axis. The ratio of velocities of VA:VB is
Answer» The displacement time graph for two particles $A$ and $B$ are straight lines inclined at angles of $30^{\circ}$ and $60^{\circ}$ with the time axis. The ratio of velocities of $V_{A} : V_{B}$ is

Discussion

21.	Which of the following are Kant's views on Noumena? A) Noumena are the limits of human understanding B) Noumena does not have a positive meaning C) Noumena must exist D) Noumena has ontological objectivity
Answer» Which of the following are Kant's views on Noumena? A) Noumena are the limits of human understanding B) Noumena does not have a positive meaning C) Noumena must exist D) Noumena has ontological objectivity

Discussion

22.	What is amplitude?
Answer» What is amplitude?

Discussion

23.	The photo electric threshold wavelength for silver is λ0). The energy of the electron ejected from the surface of silver by an incident wavelength λ(λ < λ0) will be
Answer» The photo electric threshold wavelength for silver is $λ_{0})$ . The energy of the electron ejected from the surface of silver by an incident wavelength $λ (λ$ < $λ_{0})$ will be

Discussion

24.	A body is projected from the ground with some angle to the horizontal. What happens to the angular momentum about the initial position in this motion
Answer» A body is projected from the ground with some angle to the horizontal. What happens to the angular momentum about the initial position in this motion

Discussion

25.	What happens when a person jumps from a height and flatly falls into the water?
Answer» What happens when a person jumps from a height and flatly falls into the water?

Discussion

26.	A ray is incident on a prism of μ=√2. Find the length of the optical path covered by ray inside the prism.
Answer» A ray is incident on a prism of $μ = \sqrt{2}$ . Find the length of the optical path covered by ray inside the prism.

Discussion

27.	A wave travelling on a string at a speed of 10 ms−1 causes each particle of the string to oscillate with a time period of 20 ms. (a) What is the wavelength of the wave ? (b) If the displacement of a particle is 1.5 mm at a certain instant, what will be the displacement of a particle 10 cm away from it at the same instant ?
Answer» A wave travelling on a string at a speed of $10 m s^{- 1}$ causes each particle of the string to oscillate with a time period of 20 ms. (a) What is the wavelength of the wave ? (b) If the displacement of a particle is 1.5 mm at a certain instant, what will be the displacement of a particle 10 cm away from it at the same instant ?

Discussion

28.	A boat is sent across a river with a velocity of 3 km/h. If the resultant velocity of the boat is 5 km/h, then velocity of the river flow is
Answer» A boat is sent across a river with a velocity of $3 km/h$ . If the resultant velocity of the boat is $5 km/h$ , then velocity of the river flow is

Discussion

29.	A proton is accelerated through a potential of 1V then its energy will be ?
Answer» A proton is accelerated through a potential of 1V then its energy will be ?

Discussion

30.	Corona discharge is caused by
Answer» Corona discharge is caused by

Discussion

31.	Water rises upto a height h in a capillary tube of certain diameter. This capillary tube is replaced by a similar tube of half the diameter. Now the water will rise to the height of:
Answer» Water rises upto a height $h$ in a capillary tube of certain diameter. This capillary tube is replaced by a similar tube of half the diameter. Now the water will rise to the height of:

Discussion

32.	A slab of stone of area 0.34m2 and thickness 10 cm is exposed on the lower face to steam at 100∘C. A block of ice at 0∘C rests on the upper face of the slab. In one hour, 3.6 kg of ice is melted. Assume that the heat loss from the sides is negligible. The latent heat of fusion of ice is 3.4×104Jkg−1. What is the thermal conductivity of the stone in units of Js−1m−1C−1?
Answer» A slab of stone of area $0.34 m^{2}$ and thickness 10 cm is exposed on the lower face to steam at $100^{\circ} C$ . A block of ice at $0^{\circ} C$ rests on the upper face of the slab. In one hour, 3.6 kg of ice is melted. Assume that the heat loss from the sides is negligible. The latent heat of fusion of ice is $3.4 \times 10^{4} J k g^{- 1}$ . What is the thermal conductivity of the stone in units of $J s^{- 1} m^{- 1} C^{- 1}$ ?

Discussion

33.	Two forces −→F1=2^i−5^j−6^k and −→F2=−^i+2^j−^k are acting on a body at a point (1,1,0) and (0,1,2) respectively. Find the torque acting on the body about the point (−1,0,1).
Answer» Two forces $_{1} = 2^i - 5^j - 6^k$ and $_{2} = -^i + 2^j -^k$ are acting on a body at a point $(1, 1, 0)$ and $(0, 1, 2)$ respectively. Find the torque acting on the body about the point $(- 1, 0, 1)$ .

Discussion

34.	Which of following represents SHM? V=0.7x V=-200X^2 V=-10X V=100X^2
Answer» Which of following represents SHM? V=0.7x V=-200X^2 V=-10X V=100X^2

Discussion

35.	A hammer of mass 2.5 kg moving with a speed of 1 m/s strikes ahead of a nail driving it 10 cm into the wall. Find the impulse applied by nail on the hammer
Answer» A hammer of mass $2.5 k g$ moving with a speed of $1 m / s$ strikes ahead of a nail driving it $10 c m$ into the wall. Find the impulse applied by nail on the hammer

Discussion

36.	A ball is projected with velocity u making an angle θ with the horizontal. The magnitude of velocity at the instant when it is perpendicular to its initial velocity of projection
Answer» A ball is projected with velocity u making an angle $θ$ with the horizontal. The magnitude of velocity at the instant when it is perpendicular to its initial velocity of projection

Discussion

37.	What is rate of change of acceleration called?
Answer» What is rate of change of acceleration called?

Discussion

38.	What is the difference between conductivity and mobility?
Answer» What is the difference between conductivity and mobility?

Discussion

39.	It is raining vertically with a velocity of 25 ms−1. A woman rides a bicycle with a speed of 10 ms−1 in north to south direction. What is the direction (angle with vertical) in which she should hold her umbrella to save herself from the rain?
Answer» It is raining vertically with a velocity of $25 {ms}^{- 1}$ . A woman rides a bicycle with a speed of $10 {ms}^{- 1}$ in north to south direction. What is the direction (angle with vertical) in which she should hold her umbrella to save herself from the rain?

Discussion

40.	A block of mass m = 1 kg moving on a horizontal surface with speed vi=2ms−1 enters a rough patch ranging from x = 0.10 m to x = 2.01 m. The retarding force Fr on the block in this range is inversely proportional to x over this range. Fr=−kx for 0.1<x<2.01. Fr=0 for x<0.1m and x>2.01m. What is the final speed(ms) of the block as it crosses the path? (Given: log 20.1 = 1.30)
Answer» A block of mass m = 1 kg moving on a horizontal surface with speed $v_{i} = 2 m s^{- 1}$ enters a rough patch ranging from x = 0.10 m to x = 2.01 m. The retarding force $F_{r}$ on the block in this range is inversely proportional to x over this range. $F_{r} = - \frac{k}{x}$ for $0.1 < x < 2.01$ . $F_{r} = 0$ for $x < 0.1 m$ and $x > 2.01 m$ . What is the final speed $(\frac{m}{s})$ of the block as it crosses the path? (Given: log 20.1 = 1.30)

Discussion

41.	Two simple pendulums whose lengths are 100 cm and 121 cm are suspended side by side. Their bobs are pulled together and then released. After how many minimum oscillations of the longer pendulum, will the two be in phase again.
Answer» Two simple pendulums whose lengths are $100 cm$ and $121 cm$ are suspended side by side. Their bobs are pulled together and then released. After how many minimum oscillations of the longer pendulum, will the two be in phase again.

Discussion

42.	A source is producing sound in a particular medium. If the wavelength of a sound wave produced by the source decreases, then the frequency of sound wave ___ . (Assume the conditions such as temperature, pressure, etc of the medium does not change.)
Answer» A source is producing sound in a particular medium. If the wavelength of a sound wave produced by the source decreases, then the frequency of sound wave ___ . (Assume the conditions such as temperature, pressure, etc of the medium does not change.)

Discussion

43.	A plastic circular disc of radius R is placed on a thin oil film, spread over a flat horizontal surface. The torque required to spin the disc about its central vertical axis with a constant angular velocity is proportional to :
Answer» A plastic circular disc of radius R is placed on a thin oil film, spread over a flat horizontal surface. The torque required to spin the disc about its central vertical axis with a constant angular velocity is proportional to :

43.

A plastic circular disc of radius R is placed on a thin oil film, spread over a flat horizontal surface. The torque required to spin the disc about its central vertical axis with a constant angular velocity is proportional to :

Answer»

A plastic circular disc of radius R is placed on a thin oil film, spread over a flat horizontal surface. The torque required to spin the disc about its central vertical axis with a constant angular velocity is proportional to :

Discussion

44.	Two conducting rings P and Q of radii r and 2r rotate uniformly in opposite directions with centre of mass velocities 2v and v respectively on a conducting surface S. There is a uniform magnetic field of magnitude B perpendicular to the plane of the rings. The potential difference between the highest points of the two rings is
Answer» Two conducting rings P and Q of radii r and 2r rotate uniformly in opposite directions with centre of mass velocities 2v and v respectively on a conducting surface S. There is a uniform magnetic field of magnitude B perpendicular to the plane of the rings. The potential difference between the highest points of the two rings is

Discussion

45.	There are four concentric shells A, B, C and D of radii a, 2a, 3a and 4a respectively. Shells B and D are given charges +q and –q respectively. Shell C is now earthed. The potential difference VA−VC is :
Answer» There are four concentric shells A, B, C and D of radii a, 2a, 3a and 4a respectively. Shells B and D are given charges +q and –q respectively. Shell C is now earthed. The potential difference $V_{A} - V_{C}$ is :

Discussion

46.	A cylindrical vessel contains a liquid of density ρ up to a height H. The liquid is closed by a piston of mass m and area of cross-section A. There is a small hole at the bottom of the vessel. The speed v with which the liquid comes out of the hole is
Answer» A cylindrical vessel contains a liquid of density $ρ$ up to a height $H$ . The liquid is closed by a piston of mass $m$ and area of cross-section $A$ . There is a small hole at the bottom of the vessel. The speed $v$ with which the liquid comes out of the hole is

Discussion

47.	Two cylinders of same cross-section and length L but made of two different materials of densities d1 and d2 are cemented together to form a cylinder of length 2L. The combination floats in a liquid of density d with a length L2 above the surface of the liquid. If d1<d2 then
Answer» Two cylinders of same cross-section and length $L$ but made of two different materials of densities $d_{1}$ and $d_{2}$ are cemented together to form a cylinder of length $2 L$ . The combination floats in a liquid of density $d$ with a length $\frac{L}{2}$ above the surface of the liquid. If $d_{1} < d_{2}$ then

Discussion

48.	A disc of radius 2 m and mass 100 kg rolls on a horizontal floor. Its centre of mass has a speed of 20 cm/s. How much work is needed to stop it ?
Answer» A disc of radius $2 m$ and mass $100 k g$ rolls on a horizontal floor. Its centre of mass has a speed of $20 c m / s$ . How much work is needed to stop it ?

Discussion

49.	A particle is projected vertically upwards with speed 20 m/s from top of a tower of height 20 m as shown in figure. Given B is top most point of trajectory and C is at same height as A. List-I gives certain statements regarding particle List - II gives corresponding results in SI units. Match the statements in List-I with corresponding results in List-II. List-IList-II(I)ratio of maximum height from ground (BD)(P)1√2to the initial height from ground (AD) is(II)ratio of distance travelled in 1st second to(Q)1the distance travelled in 2nd second is(III)ratio of initial speed at A to the final(R)2just before reaching to ground (D) is(IV) ratio of time taken from A to C and time (S)3taken from A to B is
Answer» A particle is projected vertically upwards with speed $20 m/s$ from top of a tower of height $20 m$ as shown in figure. Given $B$ is top most point of trajectory and $C$ is at same height as $A$ . List-I gives certain statements regarding particle List - II gives corresponding results in SI units. Match the statements in List-I with corresponding results in List-II. $\begin{matrix} List-I & List-II (I) & ratio of maximum height from ground (BD) & (P) & \frac{1}{\sqrt{2}} to the initial height from ground (AD) is (II) & ratio of distance travelled in 1^{s t} second to & (Q) & 1 the distance travelled in 2^{n d} second is (III) & ratio of initial speed at A to the final & (R) & 2 just before reaching to ground (D) is (IV) & ratio of time taken from A to C and time & (S) & 3 taken from A to B is \end{matrix}$

Discussion

50.	Explain the concept of rain-man problem in relative velocity.
Answer» Explain the concept of rain-man problem in relative velocity.

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

In the arrangement shown in figure, coefficient of friction between the two blocks is μ=12. The force of friction acting between the two blocks is

A hoop of radius 2 m weighs 100 kg. It rolls along a horizontal floor so that its centre of mass has a speed of 20 cm/s. How much work has to be done to stop it?

The displacement – time graph of a body of mass 2 kg is shown. Find the impulse acting on the body in the time interval t=2 sec to t=6 sec

I am unable to do numericals of neet papers thermodynamics and thermal properties of matter Especially the graphs too.

A gas is filled in a vessel at 27C . To what temperature should it be heated in order that 1/3rd of the gas may escape out of the vessel ?

C,Si, and Ge have the same lattice structure. Why is C insulator while Si and Ge intrinsic semiconductors?

Light of wavelength λ strikes a photo-sensitive surface and electrons are ejected with kinetic energy E. If the kinetic energy is to be increased to 2E, the wavelength must be changed to λ′ where

Acceptor circuit is

The pressure of a gas changes linearly with volume from 10 kPa, 200 cc to 50 kPa. 50 cc. (a) Calculate the work done by the gas. (b) If no heat is supplied or extracted from the gas, what is the change in the internal energy of the gas ?

What is the total distance travelled till 30 seconds?

A bob of mass 10 kg is attached to wire 0.3 m long. Its breaking stress is 4.8×107N/m2. The area of cross section of the wire is 10−6m2. The maximum angular velocity with which it can be rotated in a horizontal circle

Find the centre of mass of a uniform L shaped lamina (a thin flate plate) with dimensions as shown in figure. The mass of the lamina is 6 kg.

Four persons A,B,C and D at the corners of an square of side X move at a constant speed V. Each person maintains a direction towards the person at the next corner. The time, the persons take to meet each other is

Given that →C=→A+→B. The magnitude of →A,→B and →C are 12, 5 and 13 units respectively. The angle between →A and →B is

A body tied with string revolves uniformly in a circle. How does the angular momentum of the body change from its initial value if the string is cut suddenly?

The weight of one litre of a gas at 1atm. Pressure and 300K is 4g. At what temperature the weight of the gas is 4g when the pressure is made 0.5 atm and volume is 1 litre?

Two wires P and Q of same length and material but radii in the ratio 2 : 1 are suspended from a rigid support. Find the ratio of strain produced in the wires when both are under same force.

The displacement time graph for two particles A and B are straight lines inclined at angles of 30∘ and 60∘ with the time axis. The ratio of velocities of VA:VB is

Which of the following are Kant's views on Noumena? A) Noumena are the limits of human understanding B) Noumena does not have a positive meaning C) Noumena must exist D) Noumena has ontological objectivity

What is amplitude?

The photo electric threshold wavelength for silver is λ0). The energy of the electron ejected from the surface of silver by an incident wavelength λ(λ < λ0) will be

A body is projected from the ground with some angle to the horizontal. What happens to the angular momentum about the initial position in this motion

What happens when a person jumps from a height and flatly falls into the water?

A ray is incident on a prism of μ=√2. Find the length of the optical path covered by ray inside the prism.

A boat is sent across a river with a velocity of 3 km/h. If the resultant velocity of the boat is 5 km/h, then velocity of the river flow is

A proton is accelerated through a potential of 1V then its energy will be ?

Corona discharge is caused by

Water rises upto a height h in a capillary tube of certain diameter. This capillary tube is replaced by a similar tube of half the diameter. Now the water will rise to the height of:

Two forces −→F1=2^i−5^j−6^k and −→F2=−^i+2^j−^k are acting on a body at a point (1,1,0) and (0,1,2) respectively. Find the torque acting on the body about the point (−1,0,1).

Which of following represents SHM? V=0.7x V=-200X^2 V=-10X V=100X^2

A hammer of mass 2.5 kg moving with a speed of 1 m/s strikes ahead of a nail driving it 10 cm into the wall. Find the impulse applied by nail on the hammer

A ball is projected with velocity u making an angle θ with the horizontal. The magnitude of velocity at the instant when it is perpendicular to its initial velocity of projection

What is rate of change of acceleration called?

What is the difference between conductivity and mobility?

It is raining vertically with a velocity of 25 ms−1. A woman rides a bicycle with a speed of 10 ms−1 in north to south direction. What is the direction (angle with vertical) in which she should hold her umbrella to save herself from the rain?

Two simple pendulums whose lengths are 100 cm and 121 cm are suspended side by side. Their bobs are pulled together and then released. After how many minimum oscillations of the longer pendulum, will the two be in phase again.

A source is producing sound in a particular medium. If the wavelength of a sound wave produced by the source decreases, then the frequency of sound wave ___ . (Assume the conditions such as temperature, pressure, etc of the medium does not change.)

A plastic circular disc of radius R is placed on a thin oil film, spread over a flat horizontal surface. The torque required to spin the disc about its central vertical axis with a constant angular velocity is proportional to :

There are four concentric shells A, B, C and D of radii a, 2a, 3a and 4a respectively. Shells B and D are given charges +q and –q respectively. Shell C is now earthed. The potential difference VA−VC is :

A cylindrical vessel contains a liquid of density ρ up to a height H. The liquid is closed by a piston of mass m and area of cross-section A. There is a small hole at the bottom of the vessel. The speed v with which the liquid comes out of the hole is

Two cylinders of same cross-section and length L but made of two different materials of densities d1 and d2 are cemented together to form a cylinder of length 2L. The combination floats in a liquid of density d with a length L2 above the surface of the liquid. If d1&lt;d2 then

A disc of radius 2 m and mass 100 kg rolls on a horizontal floor. Its centre of mass has a speed of 20 cm/s. How much work is needed to stop it ?

Explain the concept of rain-man problem in relative velocity.

Two cylinders of same cross-section and length L but made of two different materials of densities d1 and d2 are cemented together to form a cylinder of length 2L. The combination floats in a liquid of density d with a length L2 above the surface of the liquid. If d1<d2 then