50278 + Interview Questions in Physics

1.	Two identical short bar magnets, each having magnetic moment M, are placed a distance of 2d apart with axes perpendicular to each other in a horizontal plane. The magnetic induction at a point midway between them is
Answer» Two identical short bar magnets, each having magnetic moment M, are placed a distance of 2d apart with axes perpendicular to each other in a horizontal plane. The magnetic induction at a point midway between them is

Discussion

2.	A point charge of 40 stat coulomb is placed 2 cm in front of an earthed metallic plane plate of large size. Then the force of attraction on the point charge is
Answer» A point charge of 40 stat coulomb is placed 2 cm in front of an earthed metallic plane plate of large size. Then the force of attraction on the point charge is

Discussion

3.	If the incident ray is rotated by an angle of 30∘ while the plane mirror is at rest, the reflected ray gets rotated by .
Answer» If the incident ray is rotated by an angle of $30^{\circ}$ while the plane mirror is at rest, the reflected ray gets rotated by .

Discussion

4.	Blocks A and C start from rest and move to the right with accelerations aA=12t m/s2 and aC=3 m/s2 respectively. Here t is in seconds. The time when block B again comes to rest is (Given that sytem starts from rest and surface is smooth).
Answer» Blocks $A$ and $C$ start from rest and move to the right with accelerations $a_{A} = 12 t {m/s}^{2}$ and $a_{C} = 3 {m/s}^{2}$ respectively. Here $t$ is in seconds. The time when block $B$ again comes to rest is (Given that sytem starts from rest and surface is smooth).

Discussion

5.	The ratio of angular speeds of second hand and minute hand of a watch is
Answer» The ratio of angular speeds of second hand and minute hand of a watch is

Discussion

6.	50g of copper is heated to increase its temperature by100C. If the same quantity of heat is given to 10g of water, the rise in its temperature is.(specific heat of copper =420 J K−1 οC−1)
Answer» $50 g$ of copper is heated to increase its temperature by $10^{0} C .$ If the same quantity of heat is given to $10 g$ of water, the rise in its temperature is. $(s p e c i f i c h e a t o f c o p p e r = 420 J K^{- 1} ο C - 1)$

Discussion

7.	The angular position of a particle is given by θ=2t2+2t−3. Find the angular velocity at t=2 sec.
Answer» The angular position of a particle is given by $θ = 2 t^{2} + 2 t - 3$ . Find the angular velocity at $t = 2 sec$ .

Discussion

8.	A block of 10 kg is being pulled by a force of 10 N. Find the acceleration of the block?
Answer» A block of 10 kg is being pulled by a force of 10 N. Find the acceleration of the block?

Discussion

9.	A car starting from rest is uniformly accelerated at the rate of 2 m/second square for 5 seconds. It then maintains a constant speed for one minute. The brakes are then applied and the car is brought to rest in 5 seconds. Find the total distance covered by the car.
Answer» A car starting from rest is uniformly accelerated at the rate of 2 m/second square for 5 seconds. It then maintains a constant speed for one minute. The brakes are then applied and the car is brought to rest in 5 seconds. Find the total distance covered by the car.

Discussion

10.	Which of the following are the units of frictional force?
Answer» Which of the following are the units of frictional force?

Discussion

11.	The electric potential at x=3 on the curve of y=x2 is 10V and it is 20 V at a point x= 4 (on the same curve). What is the average potential gradient between these two points?
Answer» The electric potential at x=3 on the curve of $y = x^{2}$ is 10V and it is 20 V at a point x= 4 (on the same curve). What is the average potential gradient between these two points?

Discussion

12.	What will be the angular position for the first minimum due to Fraunhoffer diffraction with sources of light of wave length 550 nm and slit of width 0.55 mm
Answer» What will be the angular position for the first minimum due to Fraunhoffer diffraction with sources of light of wave length 550 nm and slit of width 0.55 mm

Discussion

13.	In the given figure, the block displaces down to the equilibrium position by an amount (K, 2K and 3K represents stiffness of the respective springs)
Answer» In the given figure, the block displaces down to the equilibrium position by an amount (K, 2K and 3K represents stiffness of the respective springs)

Discussion

14.	A point particle of mass M is attached to one end of a massless rigid non-conducting rod of length L. Another point particle of same mass is attached to the other end of the rod. The two particles carry charges +q and −q repectively. This arrangement is held in a region of uniform electric field E such that the rod makes a small angle (θ<5∘) with the field direction. The minimum time needed for the rod to become parallel to the field after it is set free. (rod rotates about centre of mass)
Answer» A point particle of mass $M$ is attached to one end of a massless rigid non-conducting rod of length $L$ . Another point particle of same mass is attached to the other end of the rod. The two particles carry charges $+ q$ and $- q$ repectively. This arrangement is held in a region of uniform electric field $E$ such that the rod makes a small angle $(θ < 5^{\circ})$ with the field direction. The minimum time needed for the rod to become parallel to the field after it is set free. (rod rotates about centre of mass)

Discussion

15.	Two blocks of masses m and 2m are placed on triangular wedge by means of a massless inextensible string over a frictionless fixed pulley. Surface of contact between the masses and wedge is frictionless and wedge makes 45∘ with horizontal on both sides as shown in figure. The tensions in the string (T) is
Answer» Two blocks of masses $m$ and $2 m$ are placed on triangular wedge by means of a massless inextensible string over a frictionless fixed pulley. Surface of contact between the masses and wedge is frictionless and wedge makes $45^{\circ}$ with horizontal on both sides as shown in figure. The tensions in the string $(T)$ is

Discussion

16.	Two blocks of masses 400 g and 200 g are connected through a light string going over a pulley which is free to rotate about its axis. The pulley has a moment of inertia 1.6×10−4kg−m2 and a radius 2.0 cm. Find 'x', which is the kinetic energy of the system as the 400 g block falls through 50 cm and also find 'y', the speed of the blocks at this instant.
Answer» Two blocks of masses 400 g and 200 g are connected through a light string going over a pulley which is free to rotate about its axis. The pulley has a moment of inertia $1.6 \times 10^{- 4} k g - m^{2}$ and a radius 2.0 cm. Find 'x', which is the kinetic energy of the system as the 400 g block falls through 50 cm and also find 'y', the speed of the blocks at this instant.

Discussion

17.	The rate at which a particular decay process occurs in a radioactive sample, is proportional to the number of radioactive nuclei present. If N is the number of radioactive nuclei present at some instant, the rate of change of N is dNdt=−λN. Consider radioactive decay of A to B which may further decay either to X or to Y. λ1,λ2 and λ3 are decay constant for A to B decay, B to X decay and B to Y decay respectively. If at t=0 number of nuclei of A,B,X and Y are N0,N0, zero and zero respectively and N1,N2,N3,N4 are number of nuclei A,B,X and Y at any instant. Rate of accumulation of at any instant will be
Answer» The rate at which a particular decay process occurs in a radioactive sample, is proportional to the number of radioactive nuclei present. If N is the number of radioactive nuclei present at some instant, the rate of change of N is $\frac{d N}{d t} = - λ N$ . Consider radioactive decay of A to B which may further decay either to X or to Y. $λ_{1}, λ_{2}$ and $λ_{3}$ are decay constant for A to B decay, B to X decay and B to Y decay respectively. If at $t = 0$ number of nuclei of A,B,X and Y are $N_{0}, N_{0}$ , zero and zero respectively and $N_{1}, N_{2}, N_{3}, N_{4}$ are number of nuclei A,B,X and Y at any instant. Rate of accumulation of at any instant will be

Discussion

18.	The surface tension of a liquid is 5 N/m. If a thin film of the area 0.02 m2is formed on a loop, then its surface energy will be? //in One of the byju's video they derived that surface energy = surface tension then what is happening in the question Surface tension is already given then why it is messing up with area and asking for surface energy ?
Answer» The surface tension of a liquid is 5 N/m. If a thin film of the area 0.02 m2is formed on a loop, then its surface energy will be? //in One of the byju's video they derived that surface energy = surface tension then what is happening in the question Surface tension is already given then why it is messing up with area and asking for surface energy ?

Discussion

19.	The volume V of a monoatomic gas varies with its temperature T as shown in the graph. The ratio of work done by the gas to the heat absorbed by it when it undergoes a change from state 'A' to state 'B' is
Answer» The volume $V$ of a monoatomic gas varies with its temperature $T$ as shown in the graph. The ratio of work done by the gas to the heat absorbed by it when it undergoes a change from state 'A' to state 'B' is

Discussion

20.	A particle moves in the x-y plane under the action of a force F such that the value of its linear momentum (→P) at any time 't' is Px=2cost,Py=2sint.The angle θ between →F and →P at a given time t. will be
Answer» A particle moves in the x-y plane under the action of a force F such that the value of its linear momentum $(\to P)$ at any time 't' is $P_{x} = 2 c o s t, P_{y} = 2 s i n t$ .The angle $θ$ between $\to F$ and $\to P$ at a given time t. will be

Discussion

21.	A mass M is lowered with the help of a string by a distance x at a constant acceleration g2. The magnitude of work done by the string will be
Answer» A mass $M$ is lowered with the help of a string by a distance $x$ at a constant acceleration $\frac{g}{2}$ . The magnitude of work done by the string will be

Discussion

22.	Which of the following organometallic compounds is σ - and π - bonded?
Answer» Which of the following organometallic compounds is $σ$ - and $π$ - bonded?

Discussion

23.	Two drops of equal radius coalesce to form a bigger drop. What is the ratio of surface energy of the bigger drop to the smaller drop?
Answer» Two drops of equal radius coalesce to form a bigger drop. What is the ratio of surface energy of the bigger drop to the smaller drop?

Discussion

24.	What are the reference points in thermometer with celsius scale?
Answer» What are the reference points in thermometer with celsius scale?

Discussion

25.	A body of mass m accelerates uniformly from rest to velocity v1 in time interval T1. The instantaneous power delivered to the body as a function of time t is
Answer» A body of mass m accelerates uniformly from rest to velocity $v_{1}$ in time interval $T_{1}$ . The instantaneous power delivered to the body as a function of time t is

Discussion

26.	Power loss during transmission is calculated using the formula P=I2R but not using the formula P=VI.why?
Answer» Power loss during transmission is calculated using the formula P=I²R but not using the formula P=VI.why?

Discussion

27.	A ball of B1 of mass m moving with velocity u1 collides head on with another ball Ball B2 of the same mass at rest.Given that the coefficient of restitution is e. Answer the following questions. What will be the ratio of the velocities of two balls after collisions A. 1+e/1-e B.(1+e)/2 C.( 1-e)/2 D. e Can I get the solution sir
Answer» A ball of B₁of mass m moving with velocity u₁ collides head on with another ball Ball B₂of the same mass at rest.Given that the coefficient of restitution is e. Answer the following questions. What will be the ratio of the velocities of two balls after collisions A. 1+e/1-e B.(1+e)/2 C.( 1-e)/2 D. e Can I get the solution sir

27.

A ball of B1 of mass m moving with velocity u1 collides head on with another ball Ball B2 of the same mass at rest.Given that the coefficient of restitution is e. Answer the following questions. What will be the ratio of the velocities of two balls after collisions A. 1+e/1-e B.(1+e)/2 C.( 1-e)/2 D. e Can I get the solution sir

Answer»

A ball of B₁of mass m moving with velocity u₁ collides head on with another ball Ball B₂of the same mass at rest.Given that the coefficient of restitution is e. Answer the following questions. What will be the ratio of the velocities of two balls after collisions

A. 1+e/1-e

B.(1+e)/2

C.( 1-e)/2

D. e

Can I get the solution sir

Discussion

28.	In a forward biased p- n junction diode, the potential barrier in the depletion region is of the form:
Answer» In a forward biased p- n junction diode, the potential barrier in the depletion region is of the form:

Discussion

29.	Velocity versus displacement curve of a particle moving in straight line is shown in the figure. From a point P, a line is drawn perpendicular to displacement axis and line PR is drawn normal to the curve at P. The instantaneous acceleration of the particle at point P___.
Answer» Velocity versus displacement curve of a particle moving in straight line is shown in the figure. From a point P, a line is drawn perpendicular to displacement axis and line PR is drawn normal to the curve at P. The instantaneous acceleration of the particle at point P___.

Discussion

30.	In the presence of an electric field, why does each electron experience a force -eE in the opposite direction?
Answer» In the presence of an electric field, why does each electron experience a force -eE in the opposite direction?

Discussion

31.	If the electrical potential difference is the difference in electrical potential then how it it is a measure done with the help of test charge , then how it causes electron to flow ?
Answer» If the electrical potential difference is the difference in electrical potential then how it it is a measure done with the help of test charge , then how it causes electron to flow ?

Discussion

32.	Can you give me some examples for: Normal Force and Tangential forces
Answer» Can you give me some examples for: Normal Force and Tangential forces

32.

Can you give me some examples for: Normal Force and Tangential forces

Answer»

Can you give me some examples for:

Normal Force and

Tangential forces

Discussion

33.	How acceleration is equal to d^2x / dt^2
Answer» How acceleration is equal to d^2x / dt^2

Discussion

34.	What is a tensor ?is time scalar or vector?
Answer» What is a tensor ?is time scalar or vector?

Discussion

35.	The energy stored in a condenser of capacity C which has been raised to a potential V is given by
Answer» The energy stored in a condenser of capacity C which has been raised to a potential V is given by

Discussion

36.	Why is it dangerous to stand on the edge of platform near the line, when the train is passing by?
Answer» Why is it dangerous to stand on the edge of platform near the line, when the train is passing by?

Discussion

37.	When a body moves with a constant speed along a circle
Answer» When a body moves with a constant speed along a circle

Discussion

38.	What is the basic difference between Amplifier and Transformer?
Answer» What is the basic difference between Amplifier and Transformer?

Discussion

39.	Give the magnitude and direction of the net force acting on a) a drop of rain falling down with a constant speed, b) a cork of mass 10 g floating on water, c) a kite skilfully held stationary in the sky, d) a car moving with a constant velocity of 30 km/h on a rough road, e) a high-speed electron in space far from all material objects, and free of electric and magnetic fields.
Answer» Give the magnitude and direction of the net force acting on a) a drop of rain falling down with a constant speed, b) a cork of mass 10 g floating on water, c) a kite skilfully held stationary in the sky, d) a car moving with a constant velocity of 30 km/h on a rough road, e) a high-speed electron in space far from all material objects, and free of electric and magnetic fields.

Discussion

40.	One end of a string of length 2 m is tied to a body of mass 1 kg and is whirled about the other end in a vertical circle at an angular speed of 4 rad/s. The tension in the string when the body is at the bottommost point of its motion will be equal to Take (g = 10 m/s2)
Answer» One end of a string of length $2 m$ is tied to a body of mass $1 kg$ and is whirled about the other end in a vertical circle at an angular speed of $4 rad/s$ . The tension in the string when the body is at the bottommost point of its motion will be equal to Take $(g = 10 {m/s}^{2})$

Discussion

41.	A ball is thrown up with initial velocity u. The retardation due to the drag is proportional to the velocity with proportionality constant, β. The maximum height and the time taken to reach the maximum height are
Answer» A ball is thrown up with initial velocity $u$ . The retardation due to the drag is proportional to the velocity with proportionality constant, $β$ . The maximum height and the time taken to reach the maximum height are

Discussion

42.	The orbital angular momentum of a satellite revolving at a distance r from the centre is L. If the distance is increased to 16r , then new angular momentum will be
Answer» The orbital angular momentum of a satellite revolving at a distance r from the centre is L. If the distance is increased to 16r , then new angular momentum will be

Discussion

43.	The X-ray coming from a Coolidge tube has a cutoff wavelength of 80 pm. Find the kinetic energy of the electrons hitting the target.
Answer» The X-ray coming from a Coolidge tube has a cutoff wavelength of 80 pm. Find the kinetic energy of the electrons hitting the target.

Discussion

44.	A sample consisting of 1 mol of mono-atomic gas (CV=32R)is taken through the cycle as shown. ΔH for the overall cycle is
Answer» A sample consisting of 1 mol of mono-atomic gas $(C_{V} = \frac{3}{2} R)$ is taken through the cycle as shown. $Δ H$ for the overall cycle is

Discussion

45.	In the figure intensity from each slit S1, S2 and S3 is I0 at P. Wavelength of light is λ (D >> d) List - 1 gives some values and List - 2 gives corresponding intensity at P. If space between slits and screen is filled with fluid of refractive index 32 then correct match is List-1List-2Id2D=λPI0IId2D=λ2Q4I0IIId2D=1.5λR5I0IVd2D=2λS9I0T3I0UNone
Answer» In the figure intensity from each slit $S_{1}$ , $S_{2}$ and $S_{3}$ is $I_{0}$ at P. Wavelength of light is $λ$ (D >> d) List - 1 gives some values and List - 2 gives corresponding intensity at P. If space between slits and screen is filled with fluid of refractive index $\frac{3}{2}$ then correct match is $\begin{matrix} List-1 & List-2 I & \frac{d^{2}}{D} = λ & P & I_{0} II & \frac{d^{2}}{D} = \frac{λ}{2} & Q & 4 I_{0} III & \frac{d^{2}}{D} = 1.5 λ & R & 5 I_{0} IV & \frac{d^{2}}{D} = 2 λ & S & 9 I_{0} T & 3 I_{0} U & None \end{matrix}$

Discussion

46.	Find the acceleration of the block of mass 2m as shown in the figure. (Strings are massless and inextensible)
Answer» Find the acceleration of the block of mass $2 m$ as shown in the figure. (Strings are massless and inextensible)

Discussion

47.	A charged particle having charge q and mass m is projected into a region of uniform electric field of strength −→E0, with velocity →V0 perpendicular to −→E0. Throughout the motion, apart from electric force, the particle also experiences a dissipative force of constant magnitude qE0 and directed opposite to its velocity. If →V0\|=6 m/s, then find its speed when it has turned through an angle of 90∘. Write speed in m/s.
Answer» A charged particle having charge $q$ and mass $m$ is projected into a region of uniform electric field of strength $_{0}$ , with velocity $_{0}$ perpendicular to $_{0}$ . Throughout the motion, apart from electric force, the particle also experiences a dissipative force of constant magnitude $q E_{0}$ and directed opposite to its velocity. If $_{0} \| = 6 m/s$ , then find its speed when it has turned through an angle of $90^{\circ}$ . Write speed in m/s.

Discussion

48.	Find work done in bringing 3 particles each having mass 100gm from large distance to the vertices of an equilateral triangle of side20cm.
Answer» Find work done in bringing 3 particles each having mass 100gm from large distance to the vertices of an equilateral triangle of side20cm.

Discussion

49.	Let a spring with force constant k is compressed by x1. Stored potential energy of the spring U1 = 12 k x2 . Let it be further compressed by x2. Let it be further compressed by x2 . Change in potential energy of the spring
Answer» Let a spring with force constant k is compressed by $x_{1}$ . Stored potential energy of the spring $U_{1}$ = $\frac{1}{2}$ k $x^{2}$ . Let it be further compressed by $x_{2}$ . Let it be further compressed by $x_{2}$ . Change in potential energy of the spring

Discussion

50.	Potential (V) due to a charged conducting hollow spherical shell varies with distance (r) from centre as
Answer» Potential (V) due to a charged conducting hollow spherical shell varies with distance (r) from centre as

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

Two identical short bar magnets, each having magnetic moment M, are placed a distance of 2d apart with axes perpendicular to each other in a horizontal plane. The magnetic induction at a point midway between them is

A point charge of 40 stat coulomb is placed 2 cm in front of an earthed metallic plane plate of large size. Then the force of attraction on the point charge is

If the incident ray is rotated by an angle of 30∘ while the plane mirror is at rest, the reflected ray gets rotated by .

Blocks A and C start from rest and move to the right with accelerations aA=12t m/s2 and aC=3 m/s2 respectively. Here t is in seconds. The time when block B again comes to rest is (Given that sytem starts from rest and surface is smooth).

The ratio of angular speeds of second hand and minute hand of a watch is

50g of copper is heated to increase its temperature by100C. If the same quantity of heat is given to 10g of water, the rise in its temperature is.(specific heat of copper =420 J K−1 οC−1)

The angular position of a particle is given by θ=2t2+2t−3. Find the angular velocity at t=2 sec.

A block of 10 kg is being pulled by a force of 10 N. Find the acceleration of the block?

A car starting from rest is uniformly accelerated at the rate of 2 m/second square for 5 seconds. It then maintains a constant speed for one minute. The brakes are then applied and the car is brought to rest in 5 seconds. Find the total distance covered by the car.

Which of the following are the units of frictional force?

The electric potential at x=3 on the curve of y=x2 is 10V and it is 20 V at a point x= 4 (on the same curve). What is the average potential gradient between these two points?

What will be the angular position for the first minimum due to Fraunhoffer diffraction with sources of light of wave length 550 nm and slit of width 0.55 mm

In the given figure, the block displaces down to the equilibrium position by an amount (K, 2K and 3K represents stiffness of the respective springs)

The volume V of a monoatomic gas varies with its temperature T as shown in the graph. The ratio of work done by the gas to the heat absorbed by it when it undergoes a change from state 'A' to state 'B' is

A particle moves in the x-y plane under the action of a force F such that the value of its linear momentum (→P) at any time 't' is Px=2cost,Py=2sint.The angle θ between →F and →P at a given time t. will be

A mass M is lowered with the help of a string by a distance x at a constant acceleration g2. The magnitude of work done by the string will be

Which of the following organometallic compounds is σ - and π - bonded?

Two drops of equal radius coalesce to form a bigger drop. What is the ratio of surface energy of the bigger drop to the smaller drop?

What are the reference points in thermometer with celsius scale?

A body of mass m accelerates uniformly from rest to velocity v1 in time interval T1. The instantaneous power delivered to the body as a function of time t is

Power loss during transmission is calculated using the formula P=I2R but not using the formula P=VI.why?

In a forward biased p- n junction diode, the potential barrier in the depletion region is of the form:

Velocity versus displacement curve of a particle moving in straight line is shown in the figure. From a point P, a line is drawn perpendicular to displacement axis and line PR is drawn normal to the curve at P. The instantaneous acceleration of the particle at point P___.

In the presence of an electric field, why does each electron experience a force -eE in the opposite direction?

If the electrical potential difference is the difference in electrical potential then how it it is a measure done with the help of test charge , then how it causes electron to flow ?

Can you give me some examples for: Normal Force and Tangential forces

How acceleration is equal to d^2x / dt^2

What is a tensor ?is time scalar or vector?

The energy stored in a condenser of capacity C which has been raised to a potential V is given by

Why is it dangerous to stand on the edge of platform near the line, when the train is passing by?

When a body moves with a constant speed along a circle

What is the basic difference between Amplifier and Transformer?

One end of a string of length 2 m is tied to a body of mass 1 kg and is whirled about the other end in a vertical circle at an angular speed of 4 rad/s. The tension in the string when the body is at the bottommost point of its motion will be equal to Take (g = 10 m/s2)

A ball is thrown up with initial velocity u. The retardation due to the drag is proportional to the velocity with proportionality constant, β. The maximum height and the time taken to reach the maximum height are

The orbital angular momentum of a satellite revolving at a distance r from the centre is L. If the distance is increased to 16r , then new angular momentum will be

The X-ray coming from a Coolidge tube has a cutoff wavelength of 80 pm. Find the kinetic energy of the electrons hitting the target.

A sample consisting of 1 mol of mono-atomic gas (CV=32R)is taken through the cycle as shown. ΔH for the overall cycle is

Find the acceleration of the block of mass 2m as shown in the figure. (Strings are massless and inextensible)

Find work done in bringing 3 particles each having mass 100gm from large distance to the vertices of an equilateral triangle of side20cm.

Let a spring with force constant k is compressed by x1. Stored potential energy of the spring U1 = 12 k x2 . Let it be further compressed by x2. Let it be further compressed by x2 . Change in potential energy of the spring

Potential (V) due to a charged conducting hollow spherical shell varies with distance (r) from centre as