50278 + Interview Questions in Physics

1.	Consider a non-uniform rod of length L, whose mass per unit length λ varies as λ=k.x2L where k is a constant and x is the distance of any point on rod from its one end. Then the centre of mass of rod is at (from the same end as x)
Answer» Consider a non-uniform rod of length $L$ , whose mass per unit length $λ$ varies as $λ = \frac{k . x^{2}}{L}$ where $k$ is a constant and $x$ is the distance of any point on rod from its one end. Then the centre of mass of rod is at (from the same end as $x$ )

Discussion

2.	A point moving with constant acceleration from A to B in the straight line AB has velocities u and v at A and B respectively. Find its velocity at C, the mid point of AB.
Answer» A point moving with constant acceleration from $A$ to $B$ in the straight line $A B$ has velocities $u$ and $v$ at $A$ and $B$ respectively. Find its velocity at $C$ , the mid point of $A B$ .

Discussion

3.	a uniform electric field of 60v/m in x-y plane making an angle 120 with positive x axis the potential difference between points p[-2,3] and q[4,1]
Answer» a uniform electric field of 60v/m in x-y plane making an angle 120 with positive x axis the potential difference between points p[-2,3] and q[4,1]

Discussion

4.	How to calculate the orbital velocity?
Answer» How to calculate the orbital velocity?

Discussion

5.	A boy runs along a straight path for the first half of the distance with a velocity v1 and the second half of the distance with a velocity v2. The average velocity V is given by
Answer» A boy runs along a straight path for the first half of the distance with a velocity $v_{1}$ and the second half of the distance with a velocity $v_{2}$ . The average velocity V is given by

Discussion

6.	For any angle θ, tap the correct bubble(s).
Answer» For any angle $θ,$ tap the correct bubble(s).

Discussion

7.	A body is thrown vertically upward with a speed of 40 m/s at t =0 and another body or same mass is projected with same velocity at t =3 seconds. Time T at which they will collide is?
Answer» A body is thrown vertically upward with a speed of 40 m/s at t =0 and another body or same mass is projected with same velocity at t =3 seconds. Time T at which they will collide is?

Discussion

8.	Explain what you understand by the term electroplating. Why is it useful?
Answer» Explain what you understand by the term electroplating. Why is it useful?

Discussion

9.	a uniform bar of mass M is and lenght l is carried upward by applying a force F on its upper end. what is force at dis†an ce X from its lower end
Answer» a uniform bar of mass M is and lenght l is carried upward by applying a force F on its upper end. what is force at dis†an ce X from its lower end

Discussion

10.	If the area of the region included between the curves x2+y2=a2 and √\|x\|+√\|y\|=√a,(a>0) is ka2 sq.units. Then [k]=(where [.] denotes G.I.F.)
Answer» If the area of the region included between the curves $x^{2} + y^{2} = a^{2}$ and $\sqrt{\| x \|} + \sqrt{\| y \|} = \sqrt{a}, (a > 0)$ is $k a^{2} sq.units .$ Then $[k] =$ (where $[.]$ denotes $G . I . F .$ )

Discussion

11.	One end of a cylindrical pipe has radius of 2cm.water comes out at 10m/s. Rate at which mass is leaving the pipe is
Answer» One end of a cylindrical pipe has radius of 2cm.water comes out at 10m/s. Rate at which mass is leaving the pipe is

Discussion

12.	A mass of 100 gm is tied to one end of a string 2 m long. The body is revolving in a horizontal circle making a maximum of 200 revolutions per min. The other end of the string is fixed at the centre of the circle of revolution. The maximum tension that the string can bear is (approximately)
Answer» A mass of 100 gm is tied to one end of a string 2 m long. The body is revolving in a horizontal circle making a maximum of 200 revolutions per min. The other end of the string is fixed at the centre of the circle of revolution. The maximum tension that the string can bear is (approximately)

Discussion

13.	On interchanging the resistances, the balance point of a meter bridge shifts to the left by 10 cm. The resistance of their series combination is 1 KΩ. How much was the resistance on the left slot before interchanging the resistances?
Answer» On interchanging the resistances, the balance point of a meter bridge shifts to the left by $10 c m .$ The resistance of their series combination is $1 K Ω$ . How much was the resistance on the left slot before interchanging the resistances?

Discussion

14.	If v = Bx-²n then find acceleration
Answer» If v = Bx-²n then find acceleration

Discussion

15.	If →a=2^i+4^j+3^k,→b=^i+2^j+^k, then the scalar product and the angle between them are
Answer» If $\to a = 2^i + 4^j + 3^k, \to b =^i + 2^j +^k,$ then the scalar product and the angle between them are

Discussion

16.	The minimum distance between an object and its real image formed by a thin convex lens of focal length f is Kf. Find the value of K.
Answer» The minimum distance between an object and its real image formed by a thin convex lens of focal length $f$ is $K f$ . Find the value of $K$ .

Discussion

17.	a capacitor of capacitance c is charged to a potential difference v from a cell and then disconnected from it a charge +Q is now given to the negative plate the potential difference across the capacitor will be
Answer» a capacitor of capacitance c is charged to a potential difference v from a cell and then disconnected from it a charge +Q is now given to the negative plate the potential difference across the capacitor will be

Discussion

18.	Read each statement below carefully, and state, with reasons, if it is true or false; (a) During rolling, the force of friction acts in the same direction as the direction of motion of the CM of the body. (b) The instantaneous speed of the point of contact during rolling is zero. (c) The instantaneous acceleration of the point of contact during rolling is zero. (d) For perfect rolling motion, work done against friction is zero. (e) A wheel moving down a perfectly frictionless inclined plane will undergo slipping (not rolling) motion.
Answer» Read each statement below carefully, and state, with reasons, if it is true or false; (a) During rolling, the force of friction acts in the same direction as the direction of motion of the CM of the body. (b) The instantaneous speed of the point of contact during rolling is zero. (c) The instantaneous acceleration of the point of contact during rolling is zero. (d) For perfect rolling motion, work done against friction is zero. (e) A wheel moving down a perfectly frictionless inclined plane will undergo slipping (not rolling) motion.

Discussion

19.	The SI and CGS units of energy are joule and erg respectively. How many ergs are equal to one joule?
Answer» The SI and CGS units of energy are joule and erg respectively. How many ergs are equal to one joule?

Discussion

20.	Top view of a block on a table is shown (g = 10 m/s2). Find out the acceleration of the block, when friction is present. M = 10 kg
Answer» Top view of a block on a table is shown (g = 10 $m / s^{2}$ ). Find out the acceleration of the block, when friction is present. M = 10 kg

20.

Top view of a block on a table is shown (g = 10 m/s2). Find out the acceleration of the block, when friction is present. M = 10 kg

Answer»

Top view of a block on a table is shown (g = 10 $m / s^{2}$ ). Find out the acceleration of the block, when friction is present. M = 10 kg

Discussion

21.	A particle executing simple harmonic motion along y axis .its motion is described by the equation y=Asinwt+B.the amplitude of the shm is
Answer» A particle executing simple harmonic motion along y axis .its motion is described by the equation y=Asinwt+B.the amplitude of the shm is

Discussion

22.	92.An electric motor operate on 50V supply and current of 12A if the efficiency of motor is 30% what is resistance of winding of motor?
Answer» 92.An electric motor operate on 50V supply and current of 12A if the efficiency of motor is 30% what is resistance of winding of motor?

Discussion

23.	A man is facing East. He turns 135∘ in the anti-clockwise direction and then 90∘ in theclockwise direction. Which direction is he facing now?
Answer» A man is facing East. He turns $135^{\circ}$ in the anti-clockwise direction and then $90^{\circ}$ in theclockwise direction. Which direction is he facing now?

Discussion

24.	For an a-c circuit containing inductor only as shown. The graph of inductive reactance (XL) vs frequency f of an ac
Answer» For an a-c circuit containing inductor only as shown. The graph of inductive reactance (XL) vs frequency f of an ac

Discussion

25.	Force of attraction between the plates of a parallel plate capacitor (filled with dielectric of constant k) is
Answer» Force of attraction between the plates of a parallel plate capacitor (filled with dielectric of constant $k$ ) is

Discussion

26.	A solenoid of length 0.5 m has a radius of 1 cm and is made up of 500 turns. It carries a current of 5 A. The magnitude of magnetic field inside the solenoid is
Answer» A solenoid of length $0.5 m$ has a radius of $1 cm$ and is made up of $500$ turns. It carries a current of $5 A$ . The magnitude of magnetic field inside the solenoid is

Discussion

27.	When a load W is hung from a it extends by l. the heat producde in the proces
Answer» When a load W is hung from a it extends by l. the heat producde in the proces

Discussion

28.	Balls are thrown vertically upward in such a way that the next ball is thrown when the previous one is at the maximum height. If the maximum height is 5 m, the number of balls thrown per minute will be
Answer» Balls are thrown vertically upward in such a way that the next ball is thrown when the previous one is at the maximum height. If the maximum height is $5 m$ , the number of balls thrown per minute will be

Discussion

29.	A particle moves in a circle of radius =21/22m with constant speed 1m/sFind magnitude of average accerlation in 2 sec.
Answer» A particle moves in a circle of radius =21/22m with constant speed 1m/s Find magnitude of average accerlation in 2 sec.

Discussion

30.	Considering massless rigid rod small oscillations, the natural frequency (in rad/s) of vibration of the system is shown in the figure.
Answer» Considering massless rigid rod small oscillations, the natural frequency (in rad/s) of vibration of the system is shown in the figure.

Discussion

31.	The quarter disc of radius R (see figure) has a uniform surface charge density σ. The Z component of electric field at (0,0,Z) is found to be EZ=σfϵ0[1−Z√R2+Z2] Then, the value of 2f is
Answer» The quarter disc of radius $R$ (see figure) has a uniform surface charge density $σ$ . The $Z$ component of electric field at $(0, 0, Z)$ is found to be $E_{Z} = \frac{σ}{f ϵ_{0}} [1 - \frac{Z}{\sqrt{R^{2} + Z^{2}}}]$ Then, the value of $2 f$ is

Discussion

32.	A charged particle carrying charge 1 μC is moving with velocity (2^i+3^j+4^k) ms−1. If an external magnetic field of (5^i+3^j−6^k)×10−3 T exists in the region where the particle is moving then the force on the particle →F×10−9 N. The vector →F is-
Answer» A charged particle carrying charge $1 μ C$ is moving with velocity $(2^i + 3^j + 4^k) {ms}^{- 1} .$ If an external magnetic field of $(5^i + 3^j - 6^k) \times 10^{- 3} T$ exists in the region where the particle is moving then the force on the particle $\to F \times 10^{- 9} N .$ The vector $\to F$ is-

Discussion

33.	for a projectile motion from ground to ground if maximum height is 30√3 m and horizontal range is 120 m. find the initial velocity and angle of projection
Answer» for a projectile motion from ground to ground if maximum height is 30√3 m and horizontal range is 120 m. find the initial velocity and angle of projection

Discussion

34.	When we are increasing the intensity the frequency is also increasing thus changing so shouldn't the photoelectron show kinetic movement?
Answer» When we are increasing the intensity the frequency is also increasing thus changing so shouldn't the photoelectron show kinetic movement?

Discussion

35.	An object of length 2.0 cm is placed perpendicular to the principal axis of a convex lens of focal length 12.0 cm. Find the size of the image if the object is at the distance of 8.0 cm from the lens.
Answer» An object of length $2.0 cm$ is placed perpendicular to the principal axis of a convex lens of focal length $12.0 cm$ . Find the size of the image if the object is at the distance of $8.0 cm$ from the lens.

Discussion

36.	Two charges 4×10−9 C and −16×10−9 C are separated by a distance 20 cm in air. The position of the neutral point from the small charge is
Answer» Two charges $4 \times 10^{- 9} C$ and $- 16 \times 10^{- 9} C$ are separated by a distance $20 cm$ in air. The position of the neutral point from the small charge is

Discussion

37.	A simple microscope is rated 5 X for a normal relaxed eye. What will be its magnifying power for a relaxed farsighted eye whose near point is 40 cm?
Answer» A simple microscope is rated 5 X for a normal relaxed eye. What will be its magnifying power for a relaxed farsighted eye whose near point is 40 cm?

Discussion

38.	Five equal resistances are connected in a network as shown in figure. The net resistance between the points A and B is
Answer» Five equal resistances are connected in a network as shown in figure. The net resistance between the points $A$ and $B$ is

Discussion

39.	At a certain location in Africa, a compass points 12° west of thegeographic north. The north tip of the magnetic needle of a dip circleplaced in the plane of magnetic meridian points 60° above thehorizontal. The horizontal component of the earth’s field is measuredto be 0.16 G. Specify the direction and magnitude of the earth’s field at the location.
Answer» At a certain location in Africa, a compass points 12° west of thegeographic north. The north tip of the magnetic needle of a dip circleplaced in the plane of magnetic meridian points 60° above thehorizontal. The horizontal component of the earth’s field is measuredto be 0.16 G. Specify the direction and magnitude of the earth’s field at the location.

Discussion

40.	the number of neutrons present in deuterium is
Answer» the number of neutrons present in deuterium is

Discussion

41.	How to write wave equation
Answer» How to write wave equation

Discussion

42.	What if there are concentric circles, like the field around a straight current carryingconductor. Since the circles are concentric, the tangents are parallel, right? Will there be a uniform magnetic field then?
Answer» What if there are concentric circles, like the field around a straight current carryingconductor. Since the circles are concentric, the tangents are parallel, right? Will there be a uniform magnetic field then?

Discussion

43.	1u is equal to
Answer» 1u is equal to

Discussion

44.	The voltage-flux adjustment of a certain 1-phase 220 V induction watt-hour meter is altered so that the phase angle between the applied voltage and the flux due to it is 85∘ (instead of 90∘). The errors introduced in the reading of this meter when the current is 5 A at power factors of unity and 0.5 lagging are respectively
Answer» The voltage-flux adjustment of a certain 1-phase 220 V induction watt-hour meter is altered so that the phase angle between the applied voltage and the flux due to it is $85^{\circ}$ (instead of $90^{\circ}$ ). The errors introduced in the reading of this meter when the current is 5 A at power factors of unity and 0.5 lagging are respectively

Discussion

45.	Which of the following examples represent (nearly) simple harmonic motion and which represent periodic but not simple harmonic motion? (a) the rotation of earth about its axis. (b) motion of an oscillating mercury column in a U-tube. (c) motion of a ball bearing inside a smooth curved bowl, when released from a point slightly above the lower most point. (d) general vibrations of a polyatomic molecule about its equilibrium position
Answer» Which of the following examples represent (nearly) simple harmonic motion and which represent periodic but not simple harmonic motion? (a) the rotation of earth about its axis. (b) motion of an oscillating mercury column in a U-tube. (c) motion of a ball bearing inside a smooth curved bowl, when released from a point slightly above the lower most point. (d) general vibrations of a polyatomic molecule about its equilibrium position

Discussion

46.	A sinusoidal wave travels along a taut string of linear mass density 0.1 g/cm. The particles oscillate along y− direction and the wave moves in the positive x−direction. The amplitude and frequency of oscillation are 2 mm and 50 Hz respectively. The minimum distance between two particles oscillating in the same phase is 4 m. The tension in the string is
Answer» A sinusoidal wave travels along a taut string of linear mass density $0.1 g/cm$ . The particles oscillate along $y -$ direction and the wave moves in the positive $x -$ direction. The amplitude and frequency of oscillation are $2 mm$ and $50 Hz$ respectively. The minimum distance between two particles oscillating in the same phase is $4 m$ . The tension in the string is

Discussion

47.	Figure shows a block of mass m attached to a spring of force constant k and connected to ground by two string. In relaxed state natural length of the spring is l. In the situation shown in figure, find the tension in the strings (1) and (2).
Answer» Figure shows a block of mass $m$ attached to a spring of force constant $k$ and connected to ground by two string. In relaxed state natural length of the spring is $l$ . In the situation shown in figure, find the tension in the strings (1) and (2).

Discussion

48.	An uncharged conducting large plate is placed as shown in the figure below. Now an electric field E towards right is applied. Find the induced charge density on the right surface of the plate.
Answer» An uncharged conducting large plate is placed as shown in the figure below. Now an electric field $E$ towards right is applied. Find the induced charge density on the right surface of the plate.

Discussion

49.	A relation between velocity and acceleration is given by v=at where a=9. Claculate the displacement in 4 seconds of that particle using the method of definite integral calculus.
Answer» A relation between velocity and acceleration is given by v=at where a=9. Claculate the displacement in 4 seconds of that particle using the method of definite integral calculus.

Discussion

50.	what is the velocity of a ball thrown upward and why?
Answer» what is the velocity of a ball thrown upward and why?

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

Consider a non-uniform rod of length L, whose mass per unit length λ varies as λ=k.x2L where k is a constant and x is the distance of any point on rod from its one end. Then the centre of mass of rod is at (from the same end as x)

A point moving with constant acceleration from A to B in the straight line AB has velocities u and v at A and B respectively. Find its velocity at C, the mid point of AB.

a uniform electric field of 60v/m in x-y plane making an angle 120 with positive x axis the potential difference between points p[-2,3] and q[4,1]

How to calculate the orbital velocity?

A boy runs along a straight path for the first half of the distance with a velocity v1 and the second half of the distance with a velocity v2. The average velocity V is given by

For any angle θ, tap the correct bubble(s).

A body is thrown vertically upward with a speed of 40 m/s at t =0 and another body or same mass is projected with same velocity at t =3 seconds. Time T at which they will collide is?

Explain what you understand by the term electroplating. Why is it useful?

a uniform bar of mass M is and lenght l is carried upward by applying a force F on its upper end. what is force at dis†an ce X from its lower end

If the area of the region included between the curves x2+y2=a2 and √|x|+√|y|=√a,(a&gt;0) is ka2 sq.units. Then [k]=(where [.] denotes G.I.F.)

One end of a cylindrical pipe has radius of 2cm.water comes out at 10m/s. Rate at which mass is leaving the pipe is

A mass of 100 gm is tied to one end of a string 2 m long. The body is revolving in a horizontal circle making a maximum of 200 revolutions per min. The other end of the string is fixed at the centre of the circle of revolution. The maximum tension that the string can bear is (approximately)

On interchanging the resistances, the balance point of a meter bridge shifts to the left by 10 cm. The resistance of their series combination is 1 KΩ. How much was the resistance on the left slot before interchanging the resistances?

If v = Bx-²n then find acceleration

If →a=2^i+4^j+3^k,→b=^i+2^j+^k, then the scalar product and the angle between them are

The minimum distance between an object and its real image formed by a thin convex lens of focal length f is Kf. Find the value of K.

a capacitor of capacitance c is charged to a potential difference v from a cell and then disconnected from it a charge +Q is now given to the negative plate the potential difference across the capacitor will be

The SI and CGS units of energy are joule and erg respectively. How many ergs are equal to one joule?

Top view of a block on a table is shown (g = 10 m/s2). Find out the acceleration of the block, when friction is present. M = 10 kg

A particle executing simple harmonic motion along y axis .its motion is described by the equation y=Asinwt+B.the amplitude of the shm is

92.An electric motor operate on 50V supply and current of 12A if the efficiency of motor is 30% what is resistance of winding of motor?

A man is facing East. He turns 135∘ in the anti-clockwise direction and then 90∘ in theclockwise direction. Which direction is he facing now?

For an a-c circuit containing inductor only as shown. The graph of inductive reactance (XL) vs frequency f of an ac

Force of attraction between the plates of a parallel plate capacitor (filled with dielectric of constant k) is

A solenoid of length 0.5 m has a radius of 1 cm and is made up of 500 turns. It carries a current of 5 A. The magnitude of magnetic field inside the solenoid is

When a load W is hung from a it extends by l. the heat producde in the proces

Balls are thrown vertically upward in such a way that the next ball is thrown when the previous one is at the maximum height. If the maximum height is 5 m, the number of balls thrown per minute will be

A particle moves in a circle of radius =21/22m with constant speed 1m/sFind magnitude of average accerlation in 2 sec.

Considering massless rigid rod small oscillations, the natural frequency (in rad/s) of vibration of the system is shown in the figure.

The quarter disc of radius R (see figure) has a uniform surface charge density σ. The Z component of electric field at (0,0,Z) is found to be EZ=σfϵ0[1−Z√R2+Z2] Then, the value of 2f is

A charged particle carrying charge 1 μC is moving with velocity (2^i+3^j+4^k) ms−1. If an external magnetic field of (5^i+3^j−6^k)×10−3 T exists in the region where the particle is moving then the force on the particle →F×10−9 N. The vector →F is-

for a projectile motion from ground to ground if maximum height is 30√3 m and horizontal range is 120 m. find the initial velocity and angle of projection

When we are increasing the intensity the frequency is also increasing thus changing so shouldn't the photoelectron show kinetic movement?

An object of length 2.0 cm is placed perpendicular to the principal axis of a convex lens of focal length 12.0 cm. Find the size of the image if the object is at the distance of 8.0 cm from the lens.

Two charges 4×10−9 C and −16×10−9 C are separated by a distance 20 cm in air. The position of the neutral point from the small charge is

A simple microscope is rated 5 X for a normal relaxed eye. What will be its magnifying power for a relaxed farsighted eye whose near point is 40 cm?

Five equal resistances are connected in a network as shown in figure. The net resistance between the points A and B is

the number of neutrons present in deuterium is

How to write wave equation

What if there are concentric circles, like the field around a straight current carryingconductor. Since the circles are concentric, the tangents are parallel, right? Will there be a uniform magnetic field then?

1u is equal to

Figure shows a block of mass m attached to a spring of force constant k and connected to ground by two string. In relaxed state natural length of the spring is l. In the situation shown in figure, find the tension in the strings (1) and (2).

An uncharged conducting large plate is placed as shown in the figure below. Now an electric field E towards right is applied. Find the induced charge density on the right surface of the plate.

A relation between velocity and acceleration is given by v=at where a=9. Claculate the displacement in 4 seconds of that particle using the method of definite integral calculus.

what is the velocity of a ball thrown upward and why?

If the area of the region included between the curves x2+y2=a2 and √|x|+√|y|=√a,(a>0) is ka2 sq.units. Then [k]=(where [.] denotes G.I.F.)