3731 + Interview Questions in Physics Page 40 InterviewSolution

1951.	Evaluate ∫sec2(−3x+4)dx
Answer» Evaluate $\int {sec}^{2} (- 3 x + 4) d x$

Discussion

1952.	A copper cube of mass 200g slides down on a rough inclined plane of inclination 37∘ at a constant speed. Assume that any loss in mechanical energy goes into the copper block as thermal energy. Find the increases in the temperature of the block as it slides down through 60 cm. Specific heat capacity of copper = 420 J kg−1K−1.
Answer» A copper cube of mass 200g slides down on a rough inclined plane of inclination $37^{\circ}$ at a constant speed. Assume that any loss in mechanical energy goes into the copper block as thermal energy. Find the increases in the temperature of the block as it slides down through 60 cm. Specific heat capacity of copper = $420 J k g^{- 1} K^{- 1}$ .

Discussion

1953.	The diagram below shows a circuit used in an experiment to determine the emf and internal resistance of the cell C. A graph was plotted for the potential difference V between the terminals of the cell against the current I, which was varied by adjusting the rheostat.The graph is shown on the right; x and y are the intercepts of the graph with the axes as shown. What is the internal resistance of the cell ?
Answer» The diagram below shows a circuit used in an experiment to determine the emf and internal resistance of the cell $C$ . A graph was plotted for the potential difference $V$ between the terminals of the cell against the current $I$ , which was varied by adjusting the rheostat. The graph is shown on the right; $x$ and $y$ are the intercepts of the graph with the axes as shown. What is the internal resistance of the cell ?

Discussion

1954.	If the radius of curvature of the path of two particles of same masses are in the ratio 1:3, then in order to have same centripetal force, their velocity should be in the ratio of
Answer» If the radius of curvature of the path of two particles of same masses are in the ratio $1 : 3$ , then in order to have same centripetal force, their velocity should be in the ratio of

Discussion

1955.	The temperature coefficient of resistance of a conductor is
Answer» The temperature coefficient of resistance of a conductor is

Discussion

1956.	The momentum of a photon in an X-ray beam of 10−10 metre wavelength is
Answer» The momentum of a photon in an X-ray beam of $10^{- 10}$ metre wavelength is

Discussion

1957.	If y=(x2+2x)(3x−4), then dydx=?
Answer» $I f y = \frac{(x^{2} + 2 x)}{(3 x - 4)}, t h e n \frac{d y}{d x} = ?$

Discussion

1958.	For series L−C−R, graph between peak current and frequency (ω) shown in the figure below.The correct order for R1,R2 and R3
Answer» For series $L - C - R$ , graph between peak current and frequency ( $ω$ ) shown in the figure below. The correct order for $R_{1}, R_{2} a n d R_{3}$

Discussion

1959.	By what minimum angle the mirror must be rotated anticlockwise such that the reflected ray will become vertical?
Answer» By what minimum angle the mirror must be rotated anticlockwise such that the reflected ray will become vertical?

Discussion

1960.	A source of sound S is travelling at 1003 m/s along a road, towards a point A. When the source is 3 m away from A, a person standing at a point O on a road perpendicular to AS hears a sound of frequency v’. The distance of O from A at that time is 4m. If the original frequency is 640 Hz, then the value of v’ is (velocity of sound is 340 m/s)
Answer» A source of sound S is travelling at $\frac{100}{3} m / s$ along a road, towards a point A. When the source is 3 m away from A, a person standing at a point O on a road perpendicular to AS hears a sound of frequency v’. The distance of O from A at that time is 4m. If the original frequency is 640 Hz, then the value of v’ is (velocity of sound is 340 m/s)

Discussion

1961.	A diminished image of an object is to be obtained on a screen 1.0 m from it. This can be achieved by appropriately placing :
Answer» A diminished image of an object is to be obtained on a screen 1.0 m from it. This can be achieved by appropriately placing :

Discussion

1962.	A ray of light of intensity I is incident on a parallel glass-slab at a point A as shown in fig. It undergoes partial reflection and refraction. At each reflection 25% of incident energy is reflected. The rays AB and A'B' undergo interference. The ratio is[IIT 1990]
Answer» A ray of light of intensity I is incident on a parallel glass-slab at a point A as shown in fig. It undergoes partial reflection and refraction. At each reflection 25% of incident energy is reflected. The rays AB and A'B' undergo interference. The ratio is [IIT 1990]

1962.

A ray of light of intensity I is incident on a parallel glass-slab at a point A as shown in fig. It undergoes partial reflection and refraction. At each reflection 25% of incident energy is reflected. The rays AB and A'B' undergo interference. The ratio is[IIT 1990]

Answer»

A ray of light of intensity I is incident on a parallel glass-slab at a point A as shown in fig. It undergoes partial reflection and refraction. At each reflection 25% of incident energy is reflected. The rays AB and A'B' undergo interference. The ratio is

[IIT 1990]

Discussion

1963.	Find net capacitance between A & B
Answer» Find net capacitance between A & B

Discussion

1964.	If a particle is moving from its initial position x=−5 m to a position x=−11 m in 2 s along a straight line. What will be the average velocity of particle ?
Answer» If a particle is moving from its initial position $x = - 5 m$ to a position $x = - 11 m$ in $2 s$ along a straight line. What will be the average velocity of particle ?

Discussion

1965.	A system X is neither in thermal equilibrium with Y, nor with Z. The systems Y and Z -
Answer» A system X is neither in thermal equilibrium with Y, nor with Z. The systems Y and Z -

Discussion

1966.	A Carnot heat engine works between the temperatures 427∘C and 27∘C. What amount of heat should it consume per second to deliver mechanical work at the rate of 1.0 kW?
Answer» A Carnot heat engine works between the temperatures $427^{\circ} C$ and $27^{\circ} C$ . What amount of heat should it consume per second to deliver mechanical work at the rate of $1.0 kW$ ?

Discussion

1967.	A body falls freely from the top of a tower. It covers 36% of the total height in the last second before striking the ground level. The height of the tower is
Answer» A body falls freely from the top of a tower. It covers $36$ % of the total height in the last second before striking the ground level. The height of the tower is

Discussion

1968.	3 particles of masses 2 kg each, are placed such that 1st one lies on negative x− axis, 2nd one lies on negative y− axis and the third one lies on positive z− axis at distances of 2 m,3 m and 1 m respectively from the origin. Then the square of the distance of centre of mass of the system from the origin is
Answer» 3 particles of masses $2 kg$ each, are placed such that $1^{s t}$ one lies on negative $x -$ axis, $2^{n d}$ one lies on negative $y -$ axis and the third one lies on positive $z -$ axis at distances of $2 m, 3 m$ and $1 m$ respectively from the origin. Then the square of the distance of centre of mass of the system from the origin is

Discussion

1969.	A 1000 kg car carrying four 82 kg people travels over a "washboard” dirt road with corrugations 4.0 m apart. The car bounces with maximum amplitude when its speed is 16 km/h. when the car stops, and the people get out, by how much does the car body rise on its suspension?
Answer» A 1000 kg car carrying four 82 kg people travels over a "washboard” dirt road with corrugations 4.0 m apart. The car bounces with maximum amplitude when its speed is 16 km/h. when the car stops, and the people get out, by how much does the car body rise on its suspension?

Discussion

1970.	A wave travelling along the positive x−direction having maximum displacement along y−direction as 1 m, wavelength 2π m and frequency of 1/π Hz is represented by:
Answer» A wave travelling along the positive $x -$ direction having maximum displacement along $y -$ direction as $1 m$ , wavelength $2 π m$ and frequency of $1 / π Hz$ is represented by:

Discussion

1971.	A person standing on an open ground hears the sound of a jet aeroplane coming from north at an angle 60∘ with ground level. But he finds the aeroplane right vertically above his position. If v is the speed of sound, then speed of the plane is
Answer» A person standing on an open ground hears the sound of a jet aeroplane coming from north at an angle $60^{\circ}$ with ground level. But he finds the aeroplane right vertically above his position. If $v$ is the speed of sound, then speed of the plane is

Discussion

1972.	A battery of emf E and internal resistance r is connected to a resistor of resistance r1 and Q joules of heat is produced in a certain time t. When the same battery is connected to another resistor of resistance r2 the same quantity of heat is produced in the same time t the value of r is
Answer» A battery of emf E and internal resistance r is connected to a resistor of resistance $r_{1}$ and Q joules of heat is produced in a certain time t. When the same battery is connected to another resistor of resistance $r_{2}$ the same quantity of heat is produced in the same time t the value of r is

Discussion

1973.	A constant torque acting on a uniform circular wheel changes its angular momentum from A0 to 4A0 in 4 seconds. The magnitude of this torque is
Answer» A constant torque acting on a uniform circular wheel changes its angular momentum from $A_{0}$ to $4 A_{0}$ in $4$ seconds. The magnitude of this torque is

Discussion

1974.	A mass is supported on a frictionless horizontal surface. It is attached to a string and rotates about a fixed centre at an angular velocity ω0. If the length of the string and angular velocity are doubled, the tension in the string which was initially T0 is now
Answer» A mass is supported on a frictionless horizontal surface. It is attached to a string and rotates about a fixed centre at an angular velocity $ω_{0}$ . If the length of the string and angular velocity are doubled, the tension in the string which was initially $T_{0}$ is now

Discussion

1975.	A light beam is travelling from Region I to Region IV (refer figure). The refractive index in Region I, II, III and IV are n0,n02,n06andn08 respectively. The angle of incidence θ for which the beam just misses entering Region IV is(IIT-JEE 2008)
Answer» A light beam is travelling from Region I to Region IV (refer figure). The refractive index in Region I, II, III and IV are $n_{0}, \frac{n_{0}}{2}, \frac{n_{0}}{6} a n d \frac{n_{0}}{8}$ respectively. The angle of incidence $θ$ for which the beam just misses entering Region IV is (IIT-JEE 2008)

Discussion

1976.	What strength does a fishing line needs to stop a 10 kg salmon (fish) swimming at 9 m/s in a distance of 4.5 m ? (Assume deceleration of salmon due to fishing line is constant)
Answer» What strength does a fishing line needs to stop a $10 k g$ salmon (fish) swimming at $9 m / s$ in a distance of $4.5 m$ ? (Assume deceleration of salmon due to fishing line is constant)

Discussion

1977.	The distance x covered by a particle in one dimensional motion varies with time t as x2=at2+2bt+c. If the acceleration of the particle depends on x as x−n, where n is an integer, the value of n is ____.
Answer» The distance $x$ covered by a particle in one dimensional motion varies with time $t$ as $x^{2} = a t^{2} + 2 b t + c$ . If the acceleration of the particle depends on $x$ as $x^{- n}$ , where $n$ is an integer, the value of $n$ is ____.

Discussion

1978.	A given sample of an ideal gas occupies a volume V at a pressure P and absolute temperature T. The mass of each molecule of the gas is m. Which of the following gives the density of the gas ?
Answer» A given sample of an ideal gas occupies a volume $V$ at a pressure $P$ and absolute temperature $T$ . The mass of each molecule of the gas is $m$ . Which of the following gives the density of the gas ?

Discussion

1979.	A projectile can have the same range R for two angles of projection. If t1 and t2 be the times of flights in the two cases, then the product of the two times of flights is proportional to
Answer» A projectile can have the same range $R$ for two angles of projection. If $t_{1}$ and $t_{2}$ be the times of flights in the two cases, then the product of the two times of flights is proportional to

Discussion

1980.	Two masses 2 kg and 3 kg are attached to the end of the string passed over a frictionless pulley fixed at the the top. The tension in the string and acceleration of the masses are
Answer» Two masses $2 k g$ and $3 k g$ are attached to the end of the string passed over a frictionless pulley fixed at the the top. The tension in the string and acceleration of the masses are

Discussion

1981.	A piece of wood of mass 6 kg is floating in water with its 13rd part inside the water. On this floating piece of wood, what maximum mass can be put such that the whole of the piece of wood gets drowned in the water?
Answer» A piece of wood of mass $6 kg$ is floating in water with its $\frac{1}{3}$ rd part inside the water. On this floating piece of wood, what maximum mass can be put such that the whole of the piece of wood gets drowned in the water?

Discussion

1982.	A 50 kg person stands on a 25 kg platform. He pulls the rope which is attached to the platform through the frictionless pulleys as shown in the figure. If the platform moves upwards at a steady velocity, find the force with which man pulls the rope. Take g=10 m/s2.
Answer» A $50 kg$ person stands on a $25 kg$ platform. He pulls the rope which is attached to the platform through the frictionless pulleys as shown in the figure. If the platform moves upwards at a steady velocity, find the force with which man pulls the rope. Take $g = 10 {m/s}^{2}$ .

Discussion

1983.	Two soap bubbles of radii 4 cm and 5 cm are touching each other over a common surface S1S2 (shown in figure). Then, radius of the common surface will be
Answer» Two soap bubbles of radii $4 cm$ and $5 cm$ are touching each other over a common surface $S_{1} S_{2}$ (shown in figure). Then, radius of the common surface will be

Discussion

1984.	A spaceship of mass m0=500 kg moves in the absence of an external force with a constant velocity v0=50 m/s. To change the direction of motion, a jet engine is switched on. It starts ejecting a gas jet with velocity u=10 m/s which is constant relative to the spaceship and directed at right angles to the spaceship motion. The engine is shut down when the mass of the spaceship decreases to 400 kg. Through what angle α does the direction of motion of the spaceship deviate due to the jet engine operation? (Take ln(1.25)=0.223)
Answer» A spaceship of mass $m_{0} = 500 kg$ moves in the absence of an external force with a constant velocity $v_{0} = 50 m/s$ . To change the direction of motion, a jet engine is switched on. It starts ejecting a gas jet with velocity $u = 10 m/s$ which is constant relative to the spaceship and directed at right angles to the spaceship motion. The engine is shut down when the mass of the spaceship decreases to $400 kg$ . Through what angle $α$ does the direction of motion of the spaceship deviate due to the jet engine operation? (Take $ln (1.25) = 0.223$ )

Discussion

1985.	A ball is thrown with a velocity of 40 m/s at an angle of 60° with the horizontal from a point A on the ground. A boy simultaneously starts from A to move a constant velocity v such that the ball is always overhead the boy. Then value of v is
Answer» A ball is thrown with a velocity of $40 m/s$ at an angle of $60 °$ with the horizontal from a point $A$ on the ground. A boy simultaneously starts from $A$ to move a constant velocity $v$ such that the ball is always overhead the boy. Then value of $v$ is

Discussion

1986.	A particle of mass 'm' is projected with velocity 'v' an angle θ with the horizontal. Find its angular momentum about the point of projection when it is at the highest point of its trajectory?
Answer» A particle of mass ' $m$ ' is projected with velocity ' $v$ ' an angle $θ$ with the horizontal. Find its angular momentum about the point of projection when it is at the highest point of its trajectory?

Discussion

1987.	Compressibility factor (Z) for N2 at −23∘C and 821 atm is 1.25. Calculate the number of moles of nitrogen gas needed to fill a gas cylinder of 100 litre capacity under given condition.
Answer» Compressibility factor $(Z)$ for $N_{2}$ at $- 23^{\circ} C$ and $821 atm$ is $1.25$ . Calculate the number of moles of nitrogen gas needed to fill a gas cylinder of $100 litre$ capacity under given condition.

Discussion

1988.	Find the acceleration of the system shown in the figure.
Answer» Find the acceleration of the system shown in the figure.

Discussion

1989.	Two identical travelling waves, moving in the same direction, are out of phase by π2 rad. If amplitude of each wave is A, then find the resultant amplitude of the wave after superimposition.
Answer» Two identical travelling waves, moving in the same direction, are out of phase by $\frac{π}{2} rad$ . If amplitude of each wave is $A$ , then find the resultant amplitude of the wave after superimposition.

Discussion

1990.	In the arrangement shown in the figure, mass of the block B and A are 2m, 8m respectively. Surface between B and the floor is smooth. The block B is connected to block C by means of a pulley. If the whole system is released from rest, then find the minimum value of mass of block C so that the block A remains stationary with respect to B. Given coefficient of static friction between A and B is μ and pulley is ideal.
Answer» In the arrangement shown in the figure, mass of the block $B$ and $A$ are $2 m$ , $8 m$ respectively. Surface between $B$ and the floor is smooth. The block $B$ is connected to block $C$ by means of a pulley. If the whole system is released from rest, then find the minimum value of mass of block $C$ so that the block $A$ remains stationary with respect to $B$ . Given coefficient of static friction between $A$ and $B$ is $μ$ and pulley is ideal.

Discussion

1991.	A body of mass m1 elastically collide with another stationary body of mass m2Column - IColumn -II(a) After the collision, velocity of second(p)>1body is maximum when m1m2 is(b) After the collision, the momentum(q)<1of second body is maximum when m1m2 is(c) After the collision, K.E. of second(r)=1body is maximum when m1m2 is(D) For elastic collision, coefficient of (s)=0restitution is
Answer» A body of mass $m_{1}$ elastically collide with another stationary body of mass $m_{2}$ $\begin{matrix} Column - I & Column -II (a) After the collision, velocity of second & (p) > 1 body is maximum when \frac{m_{1}}{m_{2}} is (b) After the collision, the momentum & (q) < 1 of second body is maximum when \frac{m_{1}}{m_{2}} is (c) After the collision, K.E. of second & (r) = 1 body is maximum when \frac{m_{1}}{m_{2}} is (D) For elastic collision, coefficient of & (s) = 0 restitution is \end{matrix}$

Discussion

1992.	A point moves in a straight line under the retardation av2. If the initial velocity is u, the distance covered in 't' seconds is
Answer» A point moves in a straight line under the retardation $a v^{2}$ . If the initial velocity is $u$ , the distance covered in ' $t$ ' seconds is

Discussion

1993.	The length of a simple pendulum is increased by 44%. What is the percentage increase in its time period?
Answer» The length of a simple pendulum is increased by $44 %$ . What is the percentage increase in its time period?

Discussion

1994.	A block of mass m is sliding down on a fixed inclined plane with velocity of 2 m/s for a distance of 2 m. Angle of inclined plane is 35∘. Calculate the work done by normal reaction on the block.
Answer» A block of mass $m$ is sliding down on a fixed inclined plane with velocity of $2 m/s$ for a distance of $2 m$ . Angle of inclined plane is $35^{\circ}$ . Calculate the work done by normal reaction on the block.

Discussion

1995.	Which of the following curves shows correct relation between convective resistance (R) and radius of hot sphere (r) being placed in a stream of cold air ?
Answer» Which of the following curves shows correct relation between convective resistance $(R)$ and radius of hot sphere $(r)$ being placed in a stream of cold air ?

Discussion

1996.	The ratio of velocity of sound in air at 4 atmosphere and that at 1 atmosphere pressure would be
Answer» The ratio of velocity of sound in air at 4 atmosphere and that at 1 atmosphere pressure would be

Discussion

1997.	A robber fires 100 bullets of mass 100 gm each from a machine gun, each at a speed of 500 m/s. If the first 40 bullets are fired in 10 s, what is the average force exerted on the machine gun by the robber during this period?
Answer» A robber fires $100$ bullets of mass $100 gm$ each from a machine gun, each at a speed of $500 m/s$ . If the first $40$ bullets are fired in $10 s$ , what is the average force exerted on the machine gun by the robber during this period?

Discussion

1998.	In a transformer, the coefficient of mutual inductance between the primary and the secondary coil is 0.2 henry. When the current changes by 5 ampere/second in the primary coil, the induced e.m.f. in the secondary coil will be
Answer» In a transformer, the coefficient of mutual inductance between the primary and the secondary coil is 0.2 henry. When the current changes by 5 ampere/second in the primary coil, the induced e.m.f. in the secondary coil will be

Discussion

1999.	A ball A is falling vertically downwards with velocity v1. It strikes elastically with a wedge moving horizontally with velocity v2 as shown in figure. What must be the ratio so that the ball bounces back in vertically upwards direction relative to wedge?
Answer» A ball $A$ is falling vertically downwards with velocity $v_{1}$ . It strikes elastically with a wedge moving horizontally with velocity $v_{2}$ as shown in figure. What must be the ratio so that the ball bounces back in vertically upwards direction relative to wedge?

1999.

A ball A is falling vertically downwards with velocity v1. It strikes elastically with a wedge moving horizontally with velocity v2 as shown in figure. What must be the ratio so that the ball bounces back in vertically upwards direction relative to wedge?

Answer»

A ball $A$ is falling vertically downwards with velocity $v_{1}$ . It strikes elastically with a wedge moving horizontally with velocity $v_{2}$ as shown in figure. What must be the ratio so that the ball bounces back in vertically upwards direction relative to wedge?

Discussion

2000.	The driver of a car moving at a speed of 10 m/s applies the brakes after noticing an obstacle. The retardation due to the brakes is 4 m/s2. What is the distance travelled by the car till it stops?
Answer» The driver of a car moving at a speed of $10 m/s$ applies the brakes after noticing an obstacle. The retardation due to the brakes is $4 {m/s}^{2}$ . What is the distance travelled by the car till it stops?

Discussion

Explore topic-wise InterviewSolutions in .

Evaluate ∫sec2(−3x+4)dx

If the radius of curvature of the path of two particles of same masses are in the ratio 1:3, then in order to have same centripetal force, their velocity should be in the ratio of

The temperature coefficient of resistance of a conductor is

The momentum of a photon in an X-ray beam of 10−10 metre wavelength is

If y=(x2+2x)(3x−4), then dydx=?

For series L−C−R, graph between peak current and frequency (ω) shown in the figure below.The correct order for R1,R2 and R3

By what minimum angle the mirror must be rotated anticlockwise such that the reflected ray will become vertical?

A diminished image of an object is to be obtained on a screen 1.0 m from it. This can be achieved by appropriately placing :

A ray of light of intensity I is incident on a parallel glass-slab at a point A as shown in fig. It undergoes partial reflection and refraction. At each reflection 25% of incident energy is reflected. The rays AB and A'B' undergo interference. The ratio is[IIT 1990]

Find net capacitance between A &amp; B

If a particle is moving from its initial position x=−5 m to a position x=−11 m in 2 s along a straight line. What will be the average velocity of particle ?

A system X is neither in thermal equilibrium with Y, nor with Z. The systems Y and Z -

A Carnot heat engine works between the temperatures 427∘C and 27∘C. What amount of heat should it consume per second to deliver mechanical work at the rate of 1.0 kW?

A body falls freely from the top of a tower. It covers 36% of the total height in the last second before striking the ground level. The height of the tower is

A 1000 kg car carrying four 82 kg people travels over a "washboard” dirt road with corrugations 4.0 m apart. The car bounces with maximum amplitude when its speed is 16 km/h. when the car stops, and the people get out, by how much does the car body rise on its suspension?

A wave travelling along the positive x−direction having maximum displacement along y−direction as 1 m, wavelength 2π m and frequency of 1/π Hz is represented by:

A person standing on an open ground hears the sound of a jet aeroplane coming from north at an angle 60∘ with ground level. But he finds the aeroplane right vertically above his position. If v is the speed of sound, then speed of the plane is

A battery of emf E and internal resistance r is connected to a resistor of resistance r1 and Q joules of heat is produced in a certain time t. When the same battery is connected to another resistor of resistance r2 the same quantity of heat is produced in the same time t the value of r is

A constant torque acting on a uniform circular wheel changes its angular momentum from A0 to 4A0 in 4 seconds. The magnitude of this torque is

A mass is supported on a frictionless horizontal surface. It is attached to a string and rotates about a fixed centre at an angular velocity ω0. If the length of the string and angular velocity are doubled, the tension in the string which was initially T0 is now

A light beam is travelling from Region I to Region IV (refer figure). The refractive index in Region I, II, III and IV are n0,n02,n06andn08 respectively. The angle of incidence θ for which the beam just misses entering Region IV is(IIT-JEE 2008)

What strength does a fishing line needs to stop a 10 kg salmon (fish) swimming at 9 m/s in a distance of 4.5 m ? (Assume deceleration of salmon due to fishing line is constant)

The distance x covered by a particle in one dimensional motion varies with time t as x2=at2+2bt+c. If the acceleration of the particle depends on x as x−n, where n is an integer, the value of n is ____.

A given sample of an ideal gas occupies a volume V at a pressure P and absolute temperature T. The mass of each molecule of the gas is m. Which of the following gives the density of the gas ?

A projectile can have the same range R for two angles of projection. If t1 and t2 be the times of flights in the two cases, then the product of the two times of flights is proportional to

Two masses 2 kg and 3 kg are attached to the end of the string passed over a frictionless pulley fixed at the the top. The tension in the string and acceleration of the masses are

A piece of wood of mass 6 kg is floating in water with its 13rd part inside the water. On this floating piece of wood, what maximum mass can be put such that the whole of the piece of wood gets drowned in the water?

A 50 kg person stands on a 25 kg platform. He pulls the rope which is attached to the platform through the frictionless pulleys as shown in the figure. If the platform moves upwards at a steady velocity, find the force with which man pulls the rope. Take g=10 m/s2.

Two soap bubbles of radii 4 cm and 5 cm are touching each other over a common surface S1S2 (shown in figure). Then, radius of the common surface will be

A ball is thrown with a velocity of 40 m/s at an angle of 60° with the horizontal from a point A on the ground. A boy simultaneously starts from A to move a constant velocity v such that the ball is always overhead the boy. Then value of v is

A particle of mass 'm' is projected with velocity 'v' an angle θ with the horizontal. Find its angular momentum about the point of projection when it is at the highest point of its trajectory?

Compressibility factor (Z) for N2 at −23∘C and 821 atm is 1.25. Calculate the number of moles of nitrogen gas needed to fill a gas cylinder of 100 litre capacity under given condition.

Find the acceleration of the system shown in the figure.

Two identical travelling waves, moving in the same direction, are out of phase by π2 rad. If amplitude of each wave is A, then find the resultant amplitude of the wave after superimposition.

A point moves in a straight line under the retardation av2. If the initial velocity is u, the distance covered in 't' seconds is

The length of a simple pendulum is increased by 44%. What is the percentage increase in its time period?

A block of mass m is sliding down on a fixed inclined plane with velocity of 2 m/s for a distance of 2 m. Angle of inclined plane is 35∘. Calculate the work done by normal reaction on the block.

Which of the following curves shows correct relation between convective resistance (R) and radius of hot sphere (r) being placed in a stream of cold air ?

The ratio of velocity of sound in air at 4 atmosphere and that at 1 atmosphere pressure would be

A robber fires 100 bullets of mass 100 gm each from a machine gun, each at a speed of 500 m/s. If the first 40 bullets are fired in 10 s, what is the average force exerted on the machine gun by the robber during this period?

In a transformer, the coefficient of mutual inductance between the primary and the secondary coil is 0.2 henry. When the current changes by 5 ampere/second in the primary coil, the induced e.m.f. in the secondary coil will be

A ball A is falling vertically downwards with velocity v1. It strikes elastically with a wedge moving horizontally with velocity v2 as shown in figure. What must be the ratio so that the ball bounces back in vertically upwards direction relative to wedge?

The driver of a car moving at a speed of 10 m/s applies the brakes after noticing an obstacle. The retardation due to the brakes is 4 m/s2. What is the distance travelled by the car till it stops?

Find net capacitance between A & B