3731 + Interview Questions in Physics Page 23 InterviewSolution

1101.	A particle starts from a point with a velocity of +6 m/s and moves with an acceleration of −2 m/s2. After what time will the particle be at the starting point?
Answer» A particle starts from a point with a velocity of $+ 6 m/s$ and moves with an acceleration of $- 2 {m/s}^{2}$ . After what time will the particle be at the starting point?

Discussion

1102.	A body of mass 5 kg falls from a height of 30 metres. If all of its mechanical energy is converted into heat, then heat produced will be[Take g=9.8 m/s2 and J=4.2 J/cal]
Answer» A body of mass $5 kg$ falls from a height of $30 metres$ . If all of its mechanical energy is converted into heat, then heat produced will be $[Take g = 9.8 {m/s}^{2} and J = 4.2 J/cal]$

Discussion

1103.	In the circuit shown in figure, the voltmeter reading would be
Answer» In the circuit shown in figure, the voltmeter reading would be

Discussion

1104.	A smooth piston of mass m and cross - section area A is in equilibrium on a diatomic gas filled in a cylindrical container and there is vaccum above the piston. The piston and container are non - conducting and the height of gas column in the container is l0 at equilibrium. If the piston is displaced slightly down the equilibrium position, then the time period of its oscillation will be:
Answer» A smooth piston of mass $m$ and cross - section area $A$ is in equilibrium on a diatomic gas filled in a cylindrical container and there is vaccum above the piston. The piston and container are non - conducting and the height of gas column in the container is $l_{0}$ at equilibrium. If the piston is displaced slightly down the equilibrium position, then the time period of its oscillation will be:

Discussion

1105.	The cylindrical tube of a spray pump has radius of 5 cm, one end of which has 10 fine holes each of radius 0.1 cm. If the speed of liquid in the tube is 1 m/s, the speed of the ejection of the liquid through the holes is
Answer» The cylindrical tube of a spray pump has radius of $5 cm$ , one end of which has $10$ fine holes each of radius $0.1 cm$ . If the speed of liquid in the tube is $1 m/s$ , the speed of the ejection of the liquid through the holes is

Discussion

1106.	Two masses M and m (with M > m) are connected by means of a pulley as shown in the figure. The system is released from rest. At the instant when mass M has fallen through a distance h, the velocity of mass m will be
Answer» Two masses M and m (with M > m) are connected by means of a pulley as shown in the figure. The system is released from rest. At the instant when mass M has fallen through a distance h, the velocity of mass m will be

Discussion

1107.	Two co-axial rings having charges +Q and +2Q are placed as shown in figure. Net electric potential at point P on the axis of rings isआवेश +Q तथा +2Q वाली दो समाक्षीय वलयों को चित्रानुसार रखा जाता है। वलयों के अक्ष पर स्थित बिंदु P पर नेट विद्युत विभव है
Answer» Two co-axial rings having charges +Q and +2Q are placed as shown in figure. Net electric potential at point P on the axis of rings is आवेश +Q तथा +2Q वाली दो समाक्षीय वलयों को चित्रानुसार रखा जाता है। वलयों के अक्ष पर स्थित बिंदु P पर नेट विद्युत विभव है

Discussion

1108.	Consider a vehicle going on a horizontal road towards east. Neglect any force by the air. The frictional forces on the vehicle by the road
Answer» Consider a vehicle going on a horizontal road towards east. Neglect any force by the air. The frictional forces on the vehicle by the road

Discussion

1109.	Two perfectly elastic particles P and Q of equal mass travelling along the line joining them with velocities 15 m/sec and 10 m/sec. After collision, their velocities respectively (in m/sec) will be
Answer» Two perfectly elastic particles P and Q of equal mass travelling along the line joining them with velocities 15 m/sec and 10 m/sec. After collision, their velocities respectively (in m/sec) will be

Discussion

1110.	A 4 m long rope, having a mass of 40 g is fixed at one end and is tied to a light string at the other end. Find the tension in the string if the difference between frequencies of consecutive overtones is 40 Hz.
Answer» A $4 m$ long rope, having a mass of $40 g$ is fixed at one end and is tied to a light string at the other end. Find the tension in the string if the difference between frequencies of consecutive overtones is $40 Hz$ .

Discussion

1111.	A uniform ring of mass m is lying at a distance 1.73 a from the centre of a sphere of mass M just over the sphere where a is the small radius of the ring as well as that of the sphere. Then gravitationalforce exerted is
Answer» A uniform ring of mass m is lying at a distance 1.73 a from the centre of a sphere of mass M just over the sphere where a is the small radius of the ring as well as that of the sphere. Then gravitational force exerted is

1111.

A uniform ring of mass m is lying at a distance 1.73 a from the centre of a sphere of mass M just over the sphere where a is the small radius of the ring as well as that of the sphere. Then gravitationalforce exerted is

Answer»

A uniform ring of mass m is lying at a distance 1.73 a from the centre of a sphere of mass M just over the sphere where a is the small radius of the ring as well as that of the sphere. Then gravitational

force exerted is

Discussion

1112.	Which of following rotational physical quantities do not match to given translational analogies?
Answer» Which of following rotational physical quantities do not match to given translational analogies?

Discussion

1113.	If the charges are in equilibrium, what is the net force on the 1C charge on the right top corner if the side of the square is 1m and if they are in vacuum?
Answer» If the charges are in equilibrium, what is the net force on the 1C charge on the right top corner if the side of the square is 1m and if they are in vacuum?

1113.

If the charges are in equilibrium, what is the net force on the 1C charge on the right top corner if the side of the square is 1m and if they are in vacuum?

Answer»

If the charges are in equilibrium, what is the net force on the 1C charge on the right top corner if the side of the square is 1m and if they are in vacuum?

Discussion

1114.	Name the gate represented by the following circuit.
Answer» Name the gate represented by the following circuit.

Discussion

1115.	Find the velocity of the end B of the rigid rod if that of the end A is V0.
Answer» Find the velocity of the end $B$ of the rigid rod if that of the end $A$ is $V_{0}$ .

Discussion

1116.	Two forces $\vec{F_1}=5\hat{i}+10\hat{j}-20\hat{k}$ and →F2=10^i−5^j−20^k act on a single point. The angle between →F1 and →F2 is nearly
Answer» Two forces $\vec{F_1}=5\hat{i}+10\hat{j}-20\hat{k}$ and $_{2} = 10^i - 5^j - 20^k$ act on a single point. The angle between $_{1}$ and $_{2}$ is nearly

Discussion

1117.	In the figure shown, a hole of radius 2 cm is made in a semicircular disc of radius 6π at a distance 8 cm from the centre C of the disc. The distance of the centre of mass of this system from point C is: (COM of semicircle of radius r is at distance 4r3π from the base)
Answer» In the figure shown, a hole of radius $2 cm$ is made in a semicircular disc of radius $6 π$ at a distance $8 cm$ from the centre $C$ of the disc. The distance of the centre of mass of this system from point $C$ is: (COM of semicircle of radius $r$ is at distance $\frac{4 r}{3 π}$ from the base)

Discussion

1118.	A particle of mass ′m′ and initially at rest is acted by a force F=at. Best representation of force displacement graph is:
Answer» A particle of mass $^{'} m^{'}$ and initially at rest is acted by a force $F = a t$ . Best representation of force displacement graph is:

Discussion

1119.	Block B of mass 100 kg rests on a rough surface of friction coefficient μ=13. A rope is tied to block B as shown in figure. The maximum acceleration with which boy A of 25 kg can climb on rope without making block move is (g=10 ms−2)
Answer» Block $B$ of mass $100 kg$ rests on a rough surface of friction coefficient $μ = \frac{1}{3}$ . A rope is tied to block $B$ as shown in figure. The maximum acceleration with which boy $A$ of $25 kg$ can climb on rope without making block move is ( $g = 10 m s^{- 2}$ )

Discussion

1120.	Two particles A and B initially at rest, move towards each other by mutual force of attraction. At the instant when the speed of A is v and the speed of B is 2v, the speed of the centre of mass of the system is
Answer» Two particles A and B initially at rest, move towards each other by mutual force of attraction. At the instant when the speed of A is v and the speed of B is 2v, the speed of the centre of mass of the system is

Discussion

1121.	How does the fan help us in keeping cool?
Answer» How does the fan help us in keeping cool?

Discussion

1122.	What is the internal mechanism in a cell that keeps its voltage constant?
Answer» What is the internal mechanism in a cell that keeps its voltage constant?

Discussion

1123.	A cricketer hits a ball with a velocity 25 m/s at 60∘ above the horizontal. How far above the ground it passes over a fielder 50 m from the bat (assume the ball is struck very close to the ground)
Answer» A cricketer hits a ball with a velocity 25 m/s at $60^{\circ}$ above the horizontal. How far above the ground it passes over a fielder 50 m from the bat (assume the ball is struck very close to the ground)

Discussion

1124.	A source 's' is emitting waves, which travels through a tube of given shape. The detector 'D ' detects constructive interference of certain frequencies. If speed of wave is v and n is an integer then those frequencies are
Answer» A source ' $s$ ' is emitting waves, which travels through a tube of given shape. The detector ' $D$ ' detects constructive interference of certain frequencies. If speed of wave is $v$ and $n$ is an integer then those frequencies are

Discussion

1125.	A cork is submerged in water by a spring attached to the bottom of a bowl. When the bowl is kept in an elevator moving with acceleration downwards, the length of spring
Answer» A cork is submerged in water by a spring attached to the bottom of a bowl. When the bowl is kept in an elevator moving with acceleration downwards, the length of spring

Discussion

1126.	The position of an elevator varies with time according to the function x(t)=t2+4t+3What will be the velocity (in m/s) of the elevator at time t=4 s
Answer» The position of an elevator varies with time according to the function $x (t) = t^{2} + 4 t + 3$ What will be the velocity (in $m/s$ ) of the elevator at time $t = 4 s$

1126.

The position of an elevator varies with time according to the function x(t)=t2+4t+3What will be the velocity (in m/s) of the elevator at time t=4 s

Answer»

The position of an elevator varies with time according to the function $x (t) = t^{2} + 4 t + 3$

What will be the velocity (in $m/s$ ) of the elevator at time $t = 4 s$

Discussion

1127.	A particle performs uniform circular motion with an angular momentum L. If the frequency of particle's motion is doubled and its kinetic energy halved, the angular momentum becomes
Answer» A particle performs uniform circular motion with an angular momentum $L$ . If the frequency of particle's motion is doubled and its kinetic energy halved, the angular momentum becomes

Discussion

1128.	The water equivalent of 20 g of aluminium (specific heat 0.2 cal g−1 ∘C−1) , is
Answer» The water equivalent of $20 g$ of aluminium (specific heat $0.2 {cal g}^{- 1}^{\circ} C^{- 1}$ ) , is

Discussion

1129.	A truck moving on a smooth horizontal surface with a uniform speed u is carrying stone-dust. If a mass Δm of the stone-dust leaks from the truck in a time Δt, the force needed to keep the truck moving at its uniform speed is
Answer» A truck moving on a smooth horizontal surface with a uniform speed u is carrying stone-dust. If a mass $Δ m$ of the stone-dust leaks from the truck in a time $Δ t$ , the force needed to keep the truck moving at its uniform speed is

Discussion

1130.	At t=0, a particle starts from (−2,0) and moves towards positive x−axis with speed of v=6t2+4t m/s. The final position of the particle and the distance travelled by the particle respectively, as a function of time are
Answer» At $t = 0$ , a particle starts from $(- 2, 0)$ and moves towards positive $x -$ axis with speed of $v = 6 t^{2} + 4 t m/s$ . The final position of the particle and the distance travelled by the particle respectively, as a function of time are

Discussion

1131.	A sphere of mass m and radius r is projected along a straight line in a gravity free space with speed v. If the coefficient of viscosity of the medium in which it moves is 16π, then the distance travelled by the body before it stops is
Answer» A sphere of mass $m$ and radius $r$ is projected along a straight line in a gravity free space with speed $v$ . If the coefficient of viscosity of the medium in which it moves is $\frac{1}{6 π}$ , then the distance travelled by the body before it stops is

Discussion

1132.	The magnitude of the focal length of a diverging less is 20 cm. What is the power of this lens?
Answer» The magnitude of the focal length of a diverging less is 20 cm. What is the power of this lens?

Discussion

1133.	A particle starts with initial velocity 15 m/s. The a−x curve is shown in the figure for the motion of particle. The speed of the particle at x=5 m is
Answer» A particle starts with initial velocity $15 m/s$ . The $a - x$ curve is shown in the figure for the motion of particle. The speed of the particle at $x = 5 m$ is

Discussion

1134.	In photoelectric effect if the intensity of light is doubled then maximum kinetic energy of photoelectrons will become
Answer» In photoelectric effect if the intensity of light is doubled then maximum kinetic energy of photoelectrons will become

Discussion

1135.	Two blocks of masses m1 and m2 are connected as shown in the figure. The acceleration of the block m2 is
Answer» Two blocks of masses $m_{1}$ and $m_{2}$ are connected as shown in the figure. The acceleration of the block $m_{2}$ is

Discussion

1136.	Two air bubbles in water
Answer» Two air bubbles in water

Discussion

1137.	A satellite of mass m moves along an elliptical path around the earth. The areal velocity of the satellite is proportional to
Answer» A satellite of mass m moves along an elliptical path around the earth. The areal velocity of the satellite is proportional to

Discussion

1138.	A wire of resistor R is bent into a circular ring of radius r. Equivalent resistance between two points X and Y on its circumference, when angle XOY is α, can be given by
Answer» A wire of resistor R is bent into a circular ring of radius r. Equivalent resistance between two points X and Y on its circumference, when angle XOY is $α$ , can be given by

Discussion

1139.	A test tube of cross-sectional area a has some lead shots in it. The total mass is m. It floats upright in a liquid of density d. When pushed down a little and released, it oscillates up and down with a period T. Choose the correct relationship from the following.
Answer» A test tube of cross-sectional area $a$ has some lead shots in it. The total mass is $m$ . It floats upright in a liquid of density $d$ . When pushed down a little and released, it oscillates up and down with a period $T$ . Choose the correct relationship from the following.

Discussion

1140.	One mole of an ideal gas goes through the process P=2V21+V2. Then, the change in temperature (in K) of the gas when volume changes from 1 m3 to 2 m3 is
Answer» One mole of an ideal gas goes through the process $P = \frac{2 V^{2}}{1 + V^{2}}$ . Then, the change in temperature (in $K$ ) of the gas when volume changes from $1 m^{3}$ to $2 m^{3}$ is

Discussion

1141.	A force is equal to 85.75 dyne. If it is expressed in Newton, then the number of significant figures will be
Answer» A force is equal to $85.75 dyne$ . If it is expressed in $Newton$ , then the number of significant figures will be

Discussion

1142.	A river flows due south with a speed of 2.0 m/s. A man steers a motorboat across the river; his velocity relative to the water is 4 m/s due east. The river is 800 m wide. How much time is required to cross the river?
Answer» A river flows due south with a speed of 2.0 m/s. A man steers a motorboat across the river; his velocity relative to the water is 4 m/s due east. The river is 800 m wide. How much time is required to cross the river?

Discussion

1143.	Einstein got Nobel prize on which of the following works
Answer» Einstein got Nobel prize on which of the following works

Discussion

1144.	A string, fixed at both ends, vibrates in a resonant node with a separation of 2.0 cm between the consecutive nodes. For the next higher resonant frequency, this separation is reduced to 1.6 cm. find the length of the string.
Answer» A string, fixed at both ends, vibrates in a resonant node with a separation of 2.0 cm between the consecutive nodes. For the next higher resonant frequency, this separation is reduced to 1.6 cm. find the length of the string.

Discussion

1145.	Two thin planks are moving on four identical cylinders as shown. There is no slipping at any of the contact points. Calculate the ratio of angular speed of upper cylinders to lower cylinders
Answer» Two thin planks are moving on four identical cylinders as shown. There is no slipping at any of the contact points. Calculate the ratio of angular speed of upper cylinders to lower cylinders

Discussion

1146.	1 liter of dry air at STP expands adiabatically to a volume of 3 litres. If γ=1.4, the work done by air is (31.4=4.655) (take air to be an ideal gas)
Answer» 1 liter of dry air at STP expands adiabatically to a volume of $3$ litres. If $γ = 1.4$ , the work done by air is ( $3^{1.4} = 4.655$ ) (take air to be an ideal gas)

Discussion

1147.	Four identical thin rods of mass m and length l each, form a square frame as shown in figure. Find the MOI of the frame about an axis passing through one of its corners and perpendicular to its plane.
Answer» Four identical thin rods of mass $m$ and length $l$ each, form a square frame as shown in figure. Find the MOI of the frame about an axis passing through one of its corners and perpendicular to its plane.

Discussion

1148.	A ray of light incident on the first mirror parallel to the second and is reflected from the second mirror parallel to first mirror. The angle between two mirrors is
Answer» A ray of light incident on the first mirror parallel to the second and is reflected from the second mirror parallel to first mirror. The angle between two mirrors is

Discussion

1149.	Mass M is divided into two parts xM and (1 − x)M. For a given separation, the value of x for which the gravitational attraction between the two pieces becomes maximum is
Answer» Mass M is divided into two parts xM and (1 − x)M. For a given separation, the value of x for which the gravitational attraction between the two pieces becomes maximum is

Discussion

1150.	A ball collides directly with another ball at rest and is itself brought to rest by the impact. If one fourth of initial kinetic energy is destroyed in the collision, the coefficient of restitution of the collision is
Answer» A ball collides directly with another ball at rest and is itself brought to rest by the impact. If one fourth of initial kinetic energy is destroyed in the collision, the coefficient of restitution of the collision is

Discussion

1116.	Two forces \(\vec{F_1}=5\hat{i}+10\hat{j}-20\hat{k}\) and →F2=10^i−5^j−20^k act on a single point. The angle between →F1 and →F2 is nearly
Answer» Two forces \(\vec{F_1}=5\hat{i}+10\hat{j}-20\hat{k}\) and $_{2} = 10^i - 5^j - 20^k$ act on a single point. The angle between $_{1}$ and $_{2}$ is nearly

Explore topic-wise InterviewSolutions in .

A particle starts from a point with a velocity of +6 m/s and moves with an acceleration of −2 m/s2. After what time will the particle be at the starting point?

A body of mass 5 kg falls from a height of 30 metres. If all of its mechanical energy is converted into heat, then heat produced will be[Take g=9.8 m/s2 and J=4.2 J/cal]

In the circuit shown in figure, the voltmeter reading would be

The cylindrical tube of a spray pump has radius of 5 cm, one end of which has 10 fine holes each of radius 0.1 cm. If the speed of liquid in the tube is 1 m/s, the speed of the ejection of the liquid through the holes is

Two masses M and m (with M &gt; m) are connected by means of a pulley as shown in the figure. The system is released from rest. At the instant when mass M has fallen through a distance h, the velocity of mass m will be

Consider a vehicle going on a horizontal road towards east. Neglect any force by the air. The frictional forces on the vehicle by the road

Two perfectly elastic particles P and Q of equal mass travelling along the line joining them with velocities 15 m/sec and 10 m/sec. After collision, their velocities respectively (in m/sec) will be

A 4 m long rope, having a mass of 40 g is fixed at one end and is tied to a light string at the other end. Find the tension in the string if the difference between frequencies of consecutive overtones is 40 Hz.

A uniform ring of mass m is lying at a distance 1.73 a from the centre of a sphere of mass M just over the sphere where a is the small radius of the ring as well as that of the sphere. Then gravitationalforce exerted is

Which of following rotational physical quantities do not match to given translational analogies?

If the charges are in equilibrium, what is the net force on the 1C charge on the right top corner if the side of the square is 1m and if they are in vacuum?

Name the gate represented by the following circuit.

Find the velocity of the end B of the rigid rod if that of the end A is V0.

Two forces \(\vec{F_1}=5\hat{i}+10\hat{j}-20\hat{k}\) and →F2=10^i−5^j−20^k act on a single point. The angle between →F1 and →F2 is nearly

In the figure shown, a hole of radius 2 cm is made in a semicircular disc of radius 6π at a distance 8 cm from the centre C of the disc. The distance of the centre of mass of this system from point C is: (COM of semicircle of radius r is at distance 4r3π from the base)

A particle of mass ′m′ and initially at rest is acted by a force F=at. Best representation of force displacement graph is:

Block B of mass 100 kg rests on a rough surface of friction coefficient μ=13. A rope is tied to block B as shown in figure. The maximum acceleration with which boy A of 25 kg can climb on rope without making block move is (g=10 ms−2)

Two particles A and B initially at rest, move towards each other by mutual force of attraction. At the instant when the speed of A is v and the speed of B is 2v, the speed of the centre of mass of the system is

How does the fan help us in keeping cool?

What is the internal mechanism in a cell that keeps its voltage constant?

A cricketer hits a ball with a velocity 25 m/s at 60∘ above the horizontal. How far above the ground it passes over a fielder 50 m from the bat (assume the ball is struck very close to the ground)

A source 's' is emitting waves, which travels through a tube of given shape. The detector 'D ' detects constructive interference of certain frequencies. If speed of wave is v and n is an integer then those frequencies are

A cork is submerged in water by a spring attached to the bottom of a bowl. When the bowl is kept in an elevator moving with acceleration downwards, the length of spring

The position of an elevator varies with time according to the function x(t)=t2+4t+3What will be the velocity (in m/s) of the elevator at time t=4 s

A particle performs uniform circular motion with an angular momentum L. If the frequency of particle's motion is doubled and its kinetic energy halved, the angular momentum becomes

The water equivalent of 20 g of aluminium (specific heat 0.2 cal g−1 ∘C−1) , is

A truck moving on a smooth horizontal surface with a uniform speed u is carrying stone-dust. If a mass Δm of the stone-dust leaks from the truck in a time Δt, the force needed to keep the truck moving at its uniform speed is

At t=0, a particle starts from (−2,0) and moves towards positive x−axis with speed of v=6t2+4t m/s. The final position of the particle and the distance travelled by the particle respectively, as a function of time are

A sphere of mass m and radius r is projected along a straight line in a gravity free space with speed v. If the coefficient of viscosity of the medium in which it moves is 16π, then the distance travelled by the body before it stops is

The magnitude of the focal length of a diverging less is 20 cm. What is the power of this lens?

A particle starts with initial velocity 15 m/s. The a−x curve is shown in the figure for the motion of particle. The speed of the particle at x=5 m is

In photoelectric effect if the intensity of light is doubled then maximum kinetic energy of photoelectrons will become

Two blocks of masses m1 and m2 are connected as shown in the figure. The acceleration of the block m2 is

Two air bubbles in water

A satellite of mass m moves along an elliptical path around the earth. The areal velocity of the satellite is proportional to

A wire of resistor R is bent into a circular ring of radius r. Equivalent resistance between two points X and Y on its circumference, when angle XOY is α, can be given by

A test tube of cross-sectional area a has some lead shots in it. The total mass is m. It floats upright in a liquid of density d. When pushed down a little and released, it oscillates up and down with a period T. Choose the correct relationship from the following.

One mole of an ideal gas goes through the process P=2V21+V2. Then, the change in temperature (in K) of the gas when volume changes from 1 m3 to 2 m3 is

A force is equal to 85.75 dyne. If it is expressed in Newton, then the number of significant figures will be

A river flows due south with a speed of 2.0 m/s. A man steers a motorboat across the river; his velocity relative to the water is 4 m/s due east. The river is 800 m wide. How much time is required to cross the river?

Einstein got Nobel prize on which of the following works

A string, fixed at both ends, vibrates in a resonant node with a separation of 2.0 cm between the consecutive nodes. For the next higher resonant frequency, this separation is reduced to 1.6 cm. find the length of the string.

Two thin planks are moving on four identical cylinders as shown. There is no slipping at any of the contact points. Calculate the ratio of angular speed of upper cylinders to lower cylinders

1 liter of dry air at STP expands adiabatically to a volume of 3 litres. If γ=1.4, the work done by air is (31.4=4.655) (take air to be an ideal gas)

Four identical thin rods of mass m and length l each, form a square frame as shown in figure. Find the MOI of the frame about an axis passing through one of its corners and perpendicular to its plane.

A ray of light incident on the first mirror parallel to the second and is reflected from the second mirror parallel to first mirror. The angle between two mirrors is

Mass M is divided into two parts xM and (1 − x)M. For a given separation, the value of x for which the gravitational attraction between the two pieces becomes maximum is

A ball collides directly with another ball at rest and is itself brought to rest by the impact. If one fourth of initial kinetic energy is destroyed in the collision, the coefficient of restitution of the collision is

Two masses M and m (with M > m) are connected by means of a pulley as shown in the figure. The system is released from rest. At the instant when mass M has fallen through a distance h, the velocity of mass m will be