3731 + Interview Questions in Physics Page 1 InterviewSolution

1.	The same retarding force is applied to stop a train. The train stops after 80 m. If the speed is doubled, then the distance will be
Answer» The same retarding force is applied to stop a train. The train stops after 80 m. If the speed is doubled, then the distance will be

1.

The same retarding force is applied to stop a train. The train stops after 80 m. If the speed is doubled, then the distance will be

Answer»

The same retarding force is applied to stop a train. The train stops after 80 m. If the speed is doubled, then the distance will be

Discussion

2.	A block of wood floats in water with 45th of its volume submerged but in another liquid, it floats fully submerged. The density of the unknown liquid is (in kg/m3)
Answer» A block of wood floats in water with ${\frac{4}{5}}^{th}$ of its volume submerged but in another liquid, it floats fully submerged. The density of the unknown liquid is (in ${kg/m}^{3}$ )

Discussion

3.	A machine which is 75 percent efficient, uses 12 joules of energy in lifting up a 1 kg mass through a certain distance. The mass is then allowed to fall through that distance. The velocity at the end of its fall is (in m/s)
Answer» A machine which is 75 percent efficient, uses 12 joules of energy in lifting up a 1 kg mass through a certain distance. The mass is then allowed to fall through that distance. The velocity at the end of its fall is (in m/s)

Discussion

4.	A stone is allowed to fall from the top of a tower 80 m high and at the same time another stone is projected vertically upwards from the ground with a velocity of 20 m/s along the same line of motion. The two stones will meet after -
Answer» A stone is allowed to fall from the top of a tower $80 m$ high and at the same time another stone is projected vertically upwards from the ground with a velocity of $20 m/s$ along the same line of motion. The two stones will meet after -

Discussion

5.	A convex lens A of focal length 20 cm and a concave lens B of focal length 5 cm are kept along the same axis with a distace d between them. If a parallel beam of light falling on A leaves B as a parallel beam, then d is equal to (IIT-JEE 1985)
Answer» A convex lens A of focal length 20 cm and a concave lens B of focal length 5 cm are kept along the same axis with a distace d between them. If a parallel beam of light falling on A leaves B as a parallel beam, then d is equal to (IIT-JEE 1985)

Discussion

6.	A kid of mass 50 kg stands at the edge of a platform of radius 1 m which can be freely rotated about its axis. The moment of inertia of the platform is 0.02 kg-m2. The system is at rest. The kid throws a ball of mass 2 kg horizontally to his friend (friend standing on the ground) in a direction tangential to the rim with a speed 10 m/s as seen by his friend. The angular velocity with which the platform will start rotating in rad/s is
Answer» A kid of mass $50 kg$ stands at the edge of a platform of radius $1 m$ which can be freely rotated about its axis. The moment of inertia of the platform is $0.02 {kg-m}^{2}$ . The system is at rest. The kid throws a ball of mass $2 kg$ horizontally to his friend (friend standing on the ground) in a direction tangential to the rim with a speed $10 m/s$ as seen by his friend. The angular velocity with which the platform will start rotating in $rad/s$ is

Discussion

7.	Two cars of unequal masses use similar tyres. If they are moving at the same initial speed, the minimum stopping distance
Answer» Two cars of unequal masses use similar tyres. If they are moving at the same initial speed, the minimum stopping distance

Discussion

8.	The maximum range of a gun on horizontal terrain is 16 km. If g=10 m/s2. What must be the muzzle velocity of the shell
Answer» The maximum range of a gun on horizontal terrain is 16 km. If $g = 10 m / s^{2}$ . What must be the muzzle velocity of the shell

Discussion

9.	The temperature inside and outside of the refrigerator is 260 K and 315 K respectively. Assuming that the refrigerator cycle is reversible, calculate the heat delivered to the surroundings for every joule of work done.
Answer» The temperature inside and outside of the refrigerator is $260 K$ and $315 K$ respectively. Assuming that the refrigerator cycle is reversible, calculate the heat delivered to the surroundings for every joule of work done.

Discussion

10.	The electric potential at a point (x, y) in the x - y plane is given by V = - kxy. The field intensity at a distance r from the origin varies as
Answer» The electric potential at a point (x, y) in the x - y plane is given by V = - kxy. The field intensity at a distance r from the origin varies as

Discussion

11.	The ratio of densities of nitrogen and oxygen is 14:16. The temperature at which the speed of sound in nitrogen will be same as that in oxygen at 55∘C is
Answer» The ratio of densities of nitrogen and oxygen is 14:16. The temperature at which the speed of sound in nitrogen will be same as that in oxygen at $55^{\circ} C$ is

Discussion

12.	Two solid bodies X and Y having same volume floats in a liquid. It is observed that X floats with 50% of its volume immersed in liquid and Y floats with 25% of its volume above the liquid level. The ratio of density of X to Y is
Answer» Two solid bodies $X$ and $Y$ having same volume floats in a liquid. It is observed that $X$ floats with $50 %$ of its volume immersed in liquid and $Y$ floats with $25 %$ of its volume above the liquid level. The ratio of density of $X$ to $Y$ is

Discussion

13.	An engine pumps up 100 kg of water through a height of 10 m in 5 s. Given that the efficiency of the engine is 60%, what is the power of the engine? (Take g=10 m/s2)
Answer» An engine pumps up $100 kg$ of water through a height of $10 m$ in $5 s$ . Given that the efficiency of the engine is $60 %$ , what is the power of the engine? (Take $g = 10 m / s^{2}$ )

Discussion

14.	As shown in figure, the block B of mass m starts from the rest at the top of a wedge W of mass M. All surfaces are without friction. W can slide on the ground, B slides down onto the ground, moves along it with a speed v, has an elastic collision with wall, and climbs back onto W. Then:
Answer» As shown in figure, the block B of mass m starts from the rest at the top of a wedge W of mass M. All surfaces are without friction. W can slide on the ground, B slides down onto the ground, moves along it with a speed v, has an elastic collision with wall, and climbs back onto W. Then:

14.

As shown in figure, the block B of mass m starts from the rest at the top of a wedge W of mass M. All surfaces are without friction. W can slide on the ground, B slides down onto the ground, moves along it with a speed v, has an elastic collision with wall, and climbs back onto W. Then:

Answer»

As shown in figure, the block B of mass m starts from the rest at the top of a wedge W of mass M. All surfaces are without friction. W can slide on the ground, B slides down onto the ground, moves along it with a speed v, has an elastic collision with wall, and climbs back onto W. Then:

Discussion

15.	The value of (→A+→B)×(→A−→B) is
Answer» The value of $(\to A + \to B) \times (\to A - \to B)$ is

Discussion

16.	A block of mass m=3 kg is pulled by a force F=50 N upwards through 2 m height in vertical direction. It takes 8 seconds to lift the mass. Find the average power delivered by the force.
Answer» A block of mass $m = 3 kg$ is pulled by a force $F = 50 N$ upwards through $2 m$ height in vertical direction. It takes $8 seconds$ to lift the mass. Find the average power delivered by the force.

Discussion

17.	A small body is projected with a velocity of 20.5 ms−1 on a rough horizontal surface. The coefficient of friction (μ) between the surface changes with time (t in s) as the body moves along the surface. The velocity at the end of 4 s in ms−1 will be . (take g=10 ms−2)
Answer» A small body is projected with a velocity of $20.5 {ms}^{- 1}$ on a rough horizontal surface. The coefficient of friction $(μ)$ between the surface changes with time ( $t$ in $s$ ) as the body moves along the surface. The velocity at the end of $4 s$ in ${ms}^{- 1}$ will be . (take $g = 10 {ms}^{- 2}$ )

Discussion

18.	A stone is projected from the ground with velocity 50 ms−1 and angle of 30∘ with horizontal. It crosses a wall after 3 s. How far the stone will fall beyond the wall? (Take g=10 ms−2)
Answer» A stone is projected from the ground with velocity $50 m s^{- 1}$ and angle of $30^{\circ}$ with horizontal. It crosses a wall after $3 s$ . How far the stone will fall beyond the wall? (Take $g = 10 m s^{- 2})$

Discussion

19.	A body moves in a circle of radius 1 m. Its speed is given by v=2t2. Find the net acceleration at t=2 s
Answer» A body moves in a circle of radius $1 m$ . Its speed is given by $v = 2 t^{2}$ . Find the net acceleration at $t = 2 s$

Discussion

20.	Find the radius of gyration of a uniform disc of radius R and mass M about its edge and perpendicular to the disc.
Answer» Find the radius of gyration of a uniform disc of radius $R$ and mass $M$ about its edge and perpendicular to the disc.

Discussion

21.	A metal rod, fixed at both ends, has a length l,area of cross section A and youngs modulus Y and coefficient of linear expansion α is heated through t0 C. The work done in heating the rod is
Answer» A metal rod, fixed at both ends, has a length $l$ ,area of cross section $A$ and youngs modulus $Y$ and coefficient of linear expansion $α$ is heated through $t^{0} C$ . The work done in heating the rod is

Discussion

22.	The angular speed of seconds needle in a mechanical watch is
Answer» The angular speed of seconds needle in a mechanical watch is

Discussion

23.	Minimum value of F for which the cube begins to tip about an edge is equal to 2mgM. Then, M is -
Answer» Minimum value of $F$ for which the cube begins to tip about an edge is equal to $\frac{2 m g}{M}$ . Then, $M$ is -

Discussion

24.	Pranav once had put his finger inside the electrical socket and had gotten a bad electric shock. When he learned about random motion of electrons and then the drift speed when there is a current, he concluded that drift speed must be very high compared to the speed of random motion and that is why you get electric shocks when there is a current. Is he right?
Answer» Pranav once had put his finger inside the electrical socket and had gotten a bad electric shock. When he learned about random motion of electrons and then the drift speed when there is a current, he concluded that drift speed must be very high compared to the speed of random motion and that is why you get electric shocks when there is a current. Is he right?

Discussion

25.	A solid cylinder of mass m is kept on the edge of a plank of mass 3m and length 15 m which in turn is kept on smooth ground. The coefficient of friction between the plank and the cylinder is 0.1. The cylinder is given an impulse which imparts it a velocity of 6 m/s but no angular velocity. Find the time (jn seconds) after which the cylinder will start pure rolling.
Answer» A solid cylinder of mass $m$ is kept on the edge of a plank of mass $3 m$ and length $15 m$ which in turn is kept on smooth ground. The coefficient of friction between the plank and the cylinder is $0.1$ . The cylinder is given an impulse which imparts it a velocity of $6 m/s$ but no angular velocity. Find the time (jn seconds) after which the cylinder will start pure rolling.

Discussion

26.	Calculate the total displacement for the given velocity-time graph.
Answer» Calculate the total displacement for the given velocity-time graph.

Discussion

27.	The values of cos α, tan α, cot α, respectively if sin α=513 and π2<α<π
Answer» The values of $c o s α, t a n α, c o t α,$ respectively if $s i n α = \frac{5}{13}$ and $\frac{π}{2} < α < π$

Discussion

28.	A mass m is suspended at the end of a massless wire of length L and cross-sectional area A. If Y is the Young's modulus of the material of the wire, the frequency of oscillations along the vertical line is given by
Answer» A mass m is suspended at the end of a massless wire of length L and cross-sectional area A. If Y is the Young's modulus of the material of the wire, the frequency of oscillations along the vertical line is given by

Discussion

29.	If a sample of metal weighs 210 gm in air, 180 gm in water and 120 gm in a liquid:
Answer» If a sample of metal weighs 210 gm in air, 180 gm in water and 120 gm in a liquid:

Discussion

30.	A simple harmonic motion of a spring-block system has an amplitude A & time period T. Consider x=0 for equilibrium position. The time required by the block to travel from x=A to x=A2 is -
Answer» A simple harmonic motion of a spring-block system has an amplitude A & time period T. Consider x=0 for equilibrium position. The time required by the block to travel from $x = A t o x = \frac{A}{2}$ is -

Discussion

31.	When the tension in a metal wire is T1, its length is l1. When the tension is T2, its length is l2. The natural length of wire is
Answer» When the tension in a metal wire is $T_{1}$ , its length is $l_{1}$ . When the tension is $T_{2}$ , its length is $l_{2}$ . The natural length of wire is

Discussion

32.	A ball of mass m is thrown in air with speed v1 from a height h1 and it is at a height h2(>h1) when its speed becomes v2. Find the work done on the ball by the air resistance.
Answer» A ball of mass $m$ is thrown in air with speed $v_{1}$ from a height $h_{1}$ and it is at a height $h_{2} (> h_{1})$ when its speed becomes $v_{2}$ . Find the work done on the ball by the air resistance.

Discussion

33.	The energy required to take the electron from second orbit to third orbit of hydrogen atom is approximately
Answer» The energy required to take the electron from second orbit to third orbit of hydrogen atom is approximately

Discussion

34.	An object of mass 5 kg is attached to the hook of a spring balance and the balance is suspended vertically from the roof of a lift. The reading on the spring balance when the lift is going up with an acceleration of 0.25 m/s2 is (g=10 m/s2)
Answer» An object of mass $5 kg$ is attached to the hook of a spring balance and the balance is suspended vertically from the roof of a lift. The reading on the spring balance when the lift is going up with an acceleration of $0.25 {m/s}^{2}$ is $(g = 10 {m/s}^{2})$

Discussion

35.	In case of a simple pendulum, the time period versus length graph is correctly depicted by:
Answer» In case of a simple pendulum, the time period versus length graph is correctly depicted by:

Discussion

36.	A boy recalls the relation almost correctly but forgets where to put the constant c i.e. speed of light. He writes m=m0√1−v2, where m and m0 stand for masses and v for speed. Right place of c is
Answer» A boy recalls the relation almost correctly but forgets where to put the constant $c$ i.e. speed of light. He writes $m = \frac{m_{0}}{\sqrt{1 - v^{2}}}$ , where $m$ and $m_{0}$ stand for masses and $v$ for speed. Right place of $c$ is

Discussion

37.	A thin glass rod is bent into a semicircle of radius r. A charge +Q is uniformly distributed along the upper half and a charge –Q is uniformly distributed along the lower half, as shown in the figure. The electric field E at, P (the centre of the semicircle, is)
Answer» A thin glass rod is bent into a semicircle of radius r. A charge +Q is uniformly distributed along the upper half and a charge –Q is uniformly distributed along the lower half, as shown in the figure. The electric field E at, P (the centre of the semicircle, is)

Discussion

38.	A body having a mass of 100 gm is allowed to fall freely (from a very large height) under the action of gravity. Work done by gravity during first 10 s of journey is (Take g=10 m/s2)
Answer» A body having a mass of $100 gm$ is allowed to fall freely (from a very large height) under the action of gravity. Work done by gravity during first $10 s$ of journey is (Take $g = 10 {m/s}^{2}$ )

Discussion

39.	Laser light of wavelength 630 nm incident on a pair of slits produces an interference pattern in which the bright fringes are separated by 8.1 mm. A second light produces an interference pattern in which the fringes are separated by 7.2 mm. Then the wavelength of the second light will be
Answer» Laser light of wavelength $630 n m$ incident on a pair of slits produces an interference pattern in which the bright fringes are separated by $8.1 m m$ . A second light produces an interference pattern in which the fringes are separated by $7.2 m m$ . Then the wavelength of the second light will be

Discussion

40.	A truck has an initial velocity of 50 m/s. On the application of brakes truck stops at 200 m. The acceleration of the truck will be
Answer» A truck has an initial velocity of $50 m/s$ . On the application of brakes truck stops at $200 m$ . The acceleration of the truck will be

Discussion

41.	A particle is projected from the ground at an angle of θ with the horizontal with an initial speed of u. Find the final velocity when it is perpendicular to the initial velocity.
Answer» A particle is projected from the ground at an angle of $θ$ with the horizontal with an initial speed of $u$ . Find the final velocity when it is perpendicular to the initial velocity.

Discussion

42.	A microphone of cross-sectional area 0.80 cm2 is placed in front of a small speaker emitting 3.0 W of sound output. If the distance between the microphone and the speaker is 2.0 m, how much energy falls on the microphone in 5.0 s?
Answer» A microphone of cross-sectional area 0.80 $c m^{2}$ is placed in front of a small speaker emitting 3.0 W of sound output. If the distance between the microphone and the speaker is 2.0 m, how much energy falls on the microphone in 5.0 s?

Discussion

43.	A plane surface is inclined making an angle θ with the horizontal. From the bottom of this inclined plane, a bullet is fired with velocity v. The maximum possible range of the bullet on the inclined plane is
Answer» A plane surface is inclined making an angle $θ$ with the horizontal. From the bottom of this inclined plane, a bullet is fired with velocity $v$ . The maximum possible range of the bullet on the inclined plane is

Discussion

44.	The blocks are of mass 2 kg shown, is in equilibrium. At t=0 right spring in figure (i) and right string in figuree (ii) breaks. Find the ratio of instantaneous acceleration of blocks in fig (i) and fig (ii) (Take g=10 m/s2)
Answer» The blocks are of mass $2 kg$ shown, is in equilibrium. At $t = 0$ right spring in figure (i) and right string in figuree (ii) breaks. Find the ratio of instantaneous acceleration of blocks in fig (i) and fig (ii) (Take $g = 10 m / s^{2}$ )

Discussion

45.	Find the displacement travelled by the sphere in 1 second if the acceleration of the cube is 2 m/s2. System starts from rest and the sphere remains in contact with the cube.
Answer» Find the displacement travelled by the sphere in $1$ second if the acceleration of the cube is $2 {m/s}^{2}$ . System starts from rest and the sphere remains in contact with the cube.

Discussion

46.	Two projectiles A and B are thrown simultaneously towards each other. If the initial distance between them is 30 m and their initial velocities are VA=2^i−3^j and VB=5^i+^j. Then the minimum distance between them during their flight will be.
Answer» Two projectiles $A$ and $B$ are thrown simultaneously towards each other. If the initial distance between them is $30 m$ and their initial velocities are $V_{A} = 2^i - 3^j$ and $V_{B} = 5^i +^j$ . Then the minimum distance between them during their flight will be.

Discussion

47.	When a body is placed in surroundings at a constant temperature of 20°C, and heated by a 10−W heater, its temperature remains constant at 40°C. If the temperature of the body is now raised from 20°C to 80°C in 5 minutes at a uniform rate, the total heat it will lose to the surroundings will be
Answer» When a body is placed in surroundings at a constant temperature of $20 ° C$ , and heated by a $10 - W$ heater, its temperature remains constant at $40 ° C$ . If the temperature of the body is now raised from $20 ° C$ to $80 ° C$ in $5$ minutes at a uniform rate, the total heat it will lose to the surroundings will be

Discussion

48.	A force has been applied on a ball when it is
Answer» A force has been applied on a ball when it is

Discussion

49.	Each capacitor is of 2μFMax energy stored in capacitor between A and B [Single capacitor between A and B] in μJ is .
Answer» Each capacitor is of $2 μ F$ Max energy stored in capacitor between A and B [Single capacitor between A and B] in $μ J$ is .

Discussion

50.	An electric lamp designed for operation on 110 V C is connected to a 220 V AC supply, through a choke coil of inductance 2H, for proper operation. The angular frequency of the AC is 100√10rad/s . If a capacitor is to be used in the place of the choke coil, its capacitance must be
Answer» An electric lamp designed for operation on 110 V C is connected to a 220 V AC supply, through a choke coil of inductance 2H, for proper operation. The angular frequency of the AC is $100 \sqrt{10} r a d / s$ . If a capacitor is to be used in the place of the choke coil, its capacitance must be

Discussion

Explore topic-wise InterviewSolutions in .

The same retarding force is applied to stop a train. The train stops after 80 m. If the speed is doubled, then the distance will be

A block of wood floats in water with 45th of its volume submerged but in another liquid, it floats fully submerged. The density of the unknown liquid is (in kg/m3)

A machine which is 75 percent efficient, uses 12 joules of energy in lifting up a 1 kg mass through a certain distance. The mass is then allowed to fall through that distance. The velocity at the end of its fall is (in m/s)

A stone is allowed to fall from the top of a tower 80 m high and at the same time another stone is projected vertically upwards from the ground with a velocity of 20 m/s along the same line of motion. The two stones will meet after -

A convex lens A of focal length 20 cm and a concave lens B of focal length 5 cm are kept along the same axis with a distace d between them. If a parallel beam of light falling on A leaves B as a parallel beam, then d is equal to (IIT-JEE 1985)

Two cars of unequal masses use similar tyres. If they are moving at the same initial speed, the minimum stopping distance

The maximum range of a gun on horizontal terrain is 16 km. If g=10 m/s2. What must be the muzzle velocity of the shell

The temperature inside and outside of the refrigerator is 260 K and 315 K respectively. Assuming that the refrigerator cycle is reversible, calculate the heat delivered to the surroundings for every joule of work done.

The electric potential at a point (x, y) in the x - y plane is given by V = - kxy. The field intensity at a distance r from the origin varies as

The ratio of densities of nitrogen and oxygen is 14:16. The temperature at which the speed of sound in nitrogen will be same as that in oxygen at 55∘C is

Two solid bodies X and Y having same volume floats in a liquid. It is observed that X floats with 50% of its volume immersed in liquid and Y floats with 25% of its volume above the liquid level. The ratio of density of X to Y is

An engine pumps up 100 kg of water through a height of 10 m in 5 s. Given that the efficiency of the engine is 60%, what is the power of the engine? (Take g=10 m/s2)

As shown in figure, the block B of mass m starts from the rest at the top of a wedge W of mass M. All surfaces are without friction. W can slide on the ground, B slides down onto the ground, moves along it with a speed v, has an elastic collision with wall, and climbs back onto W. Then:

The value of (→A+→B)×(→A−→B) is

A block of mass m=3 kg is pulled by a force F=50 N upwards through 2 m height in vertical direction. It takes 8 seconds to lift the mass. Find the average power delivered by the force.

A small body is projected with a velocity of 20.5 ms−1 on a rough horizontal surface. The coefficient of friction (μ) between the surface changes with time (t in s) as the body moves along the surface. The velocity at the end of 4 s in ms−1 will be . (take g=10 ms−2)

A stone is projected from the ground with velocity 50 ms−1 and angle of 30∘ with horizontal. It crosses a wall after 3 s. How far the stone will fall beyond the wall? (Take g=10 ms−2)

A body moves in a circle of radius 1 m. Its speed is given by v=2t2. Find the net acceleration at t=2 s

Find the radius of gyration of a uniform disc of radius R and mass M about its edge and perpendicular to the disc.

A metal rod, fixed at both ends, has a length l,area of cross section A and youngs modulus Y and coefficient of linear expansion α is heated through t0 C. The work done in heating the rod is

The angular speed of seconds needle in a mechanical watch is

Minimum value of F for which the cube begins to tip about an edge is equal to 2mgM. Then, M is -

Calculate the total displacement for the given velocity-time graph.

The values of cos α, tan α, cot α, respectively if sin α=513 and π2&lt;α&lt;π

A mass m is suspended at the end of a massless wire of length L and cross-sectional area A. If Y is the Young's modulus of the material of the wire, the frequency of oscillations along the vertical line is given by

If a sample of metal weighs 210 gm in air, 180 gm in water and 120 gm in a liquid:

A simple harmonic motion of a spring-block system has an amplitude A &amp; time period T. Consider x=0 for equilibrium position. The time required by the block to travel from x=A to x=A2 is -

When the tension in a metal wire is T1, its length is l1. When the tension is T2, its length is l2. The natural length of wire is

A ball of mass m is thrown in air with speed v1 from a height h1 and it is at a height h2(&gt;h1) when its speed becomes v2. Find the work done on the ball by the air resistance.

The energy required to take the electron from second orbit to third orbit of hydrogen atom is approximately

An object of mass 5 kg is attached to the hook of a spring balance and the balance is suspended vertically from the roof of a lift. The reading on the spring balance when the lift is going up with an acceleration of 0.25 m/s2 is (g=10 m/s2)

In case of a simple pendulum, the time period versus length graph is correctly depicted by:

A boy recalls the relation almost correctly but forgets where to put the constant c i.e. speed of light. He writes m=m0√1−v2, where m and m0 stand for masses and v for speed. Right place of c is

A thin glass rod is bent into a semicircle of radius r. A charge +Q is uniformly distributed along the upper half and a charge –Q is uniformly distributed along the lower half, as shown in the figure. The electric field E at, P (the centre of the semicircle, is)

A body having a mass of 100 gm is allowed to fall freely (from a very large height) under the action of gravity. Work done by gravity during first 10 s of journey is (Take g=10 m/s2)

Laser light of wavelength 630 nm incident on a pair of slits produces an interference pattern in which the bright fringes are separated by 8.1 mm. A second light produces an interference pattern in which the fringes are separated by 7.2 mm. Then the wavelength of the second light will be

A truck has an initial velocity of 50 m/s. On the application of brakes truck stops at 200 m. The acceleration of the truck will be

A particle is projected from the ground at an angle of θ with the horizontal with an initial speed of u. Find the final velocity when it is perpendicular to the initial velocity.

A microphone of cross-sectional area 0.80 cm2 is placed in front of a small speaker emitting 3.0 W of sound output. If the distance between the microphone and the speaker is 2.0 m, how much energy falls on the microphone in 5.0 s?

A plane surface is inclined making an angle θ with the horizontal. From the bottom of this inclined plane, a bullet is fired with velocity v. The maximum possible range of the bullet on the inclined plane is

The blocks are of mass 2 kg shown, is in equilibrium. At t=0 right spring in figure (i) and right string in figuree (ii) breaks. Find the ratio of instantaneous acceleration of blocks in fig (i) and fig (ii) (Take g=10 m/s2)

Find the displacement travelled by the sphere in 1 second if the acceleration of the cube is 2 m/s2. System starts from rest and the sphere remains in contact with the cube.

Two projectiles A and B are thrown simultaneously towards each other. If the initial distance between them is 30 m and their initial velocities are VA=2^i−3^j and VB=5^i+^j. Then the minimum distance between them during their flight will be.

A force has been applied on a ball when it is

Each capacitor is of 2μFMax energy stored in capacitor between A and B [Single capacitor between A and B] in μJ is .

An electric lamp designed for operation on 110 V C is connected to a 220 V AC supply, through a choke coil of inductance 2H, for proper operation. The angular frequency of the AC is 100√10rad/s . If a capacitor is to be used in the place of the choke coil, its capacitance must be

The values of cos α, tan α, cot α, respectively if sin α=513 and π2<α<π

A simple harmonic motion of a spring-block system has an amplitude A & time period T. Consider x=0 for equilibrium position. The time required by the block to travel from x=A to x=A2 is -

A ball of mass m is thrown in air with speed v1 from a height h1 and it is at a height h2(>h1) when its speed becomes v2. Find the work done on the ball by the air resistance.