50278 + Interview Questions in Physics

1.	Gases show positive deviations when:
Answer» Gases show positive deviations when:

Discussion

2.	The speed of transverse waves on a string depends upon
Answer» The speed of transverse waves on a string depends upon

Discussion

3.	A 50 g bullet moving with velocity 10 m/s strikes a block of mass 950 g at rest and gets embedded in it. The loss in kinetic energy will be
Answer» A 50 g bullet moving with velocity 10 m/s strikes a block of mass 950 g at rest and gets embedded in it. The loss in kinetic energy will be

Discussion

4.	What is the Reaumur temperature scale? Give the advantage and disadvantage of Reaumur scale thermometer.
Answer» What is the Reaumur temperature scale? Give the advantage and disadvantage of Reaumur scale thermometer.

Discussion

5.	If black wire of platinum is heated, then its colour first appear red, then yellow and finally white. It can be understood on the basis of
Answer» If black wire of platinum is heated, then its colour first appear red, then yellow and finally white. It can be understood on the basis of

Discussion

6.	If the velocity of sound in air is 350 m/s. Then the fundamental frequency of an open organ pipe of length 50 cm, will be
Answer» If the velocity of sound in air is 350 m/s. Then the fundamental frequency of an open organ pipe of length 50 cm, will be

6.

If the velocity of sound in air is 350 m/s. Then the fundamental frequency of an open organ pipe of length 50 cm, will be

Answer»

If the velocity of sound in air is 350 m/s. Then the fundamental frequency of

an open organ pipe of length 50 cm, will be

Discussion

7.	A body released from a height h takes time t to reach earth’s surface. The time taken by the same body released from the same height to reach the moon’s surface is
Answer» A body released from a height h takes time t to reach earth’s surface. The time taken by the same body released from the same height to reach the moon’s surface is

Discussion

8.	An object of mass M is kept on a rough table as seen from above. Forces are applied as shown. Find the direction (from the vertical) of static friction if the object does not move.
Answer» An object of mass $M$ is kept on a rough table as seen from above. Forces are applied as shown. Find the direction (from the vertical) of static friction if the object does not move.

Discussion

9.	If a hole is bored along the diameter of the earth and a stone is dropped into hole
Answer» If a hole is bored along the diameter of the earth and a stone is dropped into hole

Discussion

10.	A long horizontal rod has a bead which can slide along its length, and initially placed at a distance L from one end A of the rod. The rod is set in angular motion about A with constant angular acceleration a. If the coefficient of friction between the rod and the bead is m, and gravity is neglected, then the time after which the bead starts slipping is
Answer» A long horizontal rod has a bead which can slide along its length, and initially placed at a distance $L$ from one end $A$ of the rod. The rod is set in angular motion about $A$ with constant angular acceleration $a$ . If the coefficient of friction between the rod and the bead is $m$ , and gravity is neglected, then the time after which the bead starts slipping is

Discussion

11.	Ship A is sailing towards north-east with velocity →v=30^i+50^j km/hr where ^i points east and ^j towards north. Ship B is at a distance of 80 km east and 150 km north of Ship A and is sailing towards west at 10 km/hr. Time in which A will be at minimum distance from B is
Answer» Ship $A$ is sailing towards north-east with velocity $\to v = 30^i + 50^j k m / h r$ where $^i$ points east and $^j$ towards north. Ship $B$ is at a distance of $80 k m$ east and $150 k m$ north of Ship $A$ and is sailing towards west at $10 k m / h r$ . Time in which $A$ will be at minimum distance from $B$ is

Discussion

12.	Which of the following results is true?
Answer» Which of the following results is true?

Discussion

13.	Two putty balls of equal mass moving with equal velocity in mutually perpendicular directions, stick together after collision. If the balls were initially moving with a velocity of 45√2 ms−1 each, the velocity of their combined mass after collision is
Answer» Two putty balls of equal mass moving with equal velocity in mutually perpendicular directions, stick together after collision. If the balls were initially moving with a velocity of $45 \sqrt{2} m s^{- 1}$ each, the velocity of their combined mass after collision is

Discussion

14.	Two balls are projected from the same point in directions inclined at 600 and 300 to the horizontal. If they attain the same height, the ratio of their velocity of projection would be (g = 9.8 ms−2).
Answer» Two balls are projected from the same point in directions inclined at $60^{0} a n d 30^{0}$ to the horizontal. If they attain the same height, the ratio of their velocity of projection would be (g = 9.8 $m s^{- 2})$ .

Discussion

15.	A remote-sensing satellite of earth revolves in a circular orbit at a height of 0.25×106 m above the surface of earth. If earth's radius is 6.4×106 m and g=9.8 ms−2, then the orbital speed of the satellite is
Answer» A remote-sensing satellite of earth revolves in a circular orbit at a height of $0.25 \times 10^{6}$ $m$ above the surface of earth. If earth's radius is $6.4 \times 10^{6} m$ and $g = 9.8 m s^{- 2}$ , then the orbital speed of the satellite is

Discussion

16.	Two metallic spheres S1 and S2 are made of the same material and have identical surface finish. The mass of S1 is three times that of S2. Both the spheres are heated to the same high temperature and place in the same room having lower temperature but are thermally insulated from each other. The ratio of the initial rate of cooling of S1 to that of S2 is
Answer» Two metallic spheres $S_{1} a n d S_{2}$ are made of the same material and have identical surface finish. The mass of $S_{1}$ is three times that of $S_{2}$ . Both the spheres are heated to the same high temperature and place in the same room having lower temperature but are thermally insulated from each other. The ratio of the initial rate of cooling of $S_{1}$ to that of $S_{2}$ is

Discussion

17.	A string is stretched between fixed points separated by 75.0 cm. It is observed to have resonant frequencies of 420 Hz and 315 Hz. There are no other resonant frequencies between these two. The lowest resonant frequency for this string is
Answer» A string is stretched between fixed points separated by $75.0 c m$ . It is observed to have resonant frequencies of $420 H z$ and $315 H z$ . There are no other resonant frequencies between these two. The lowest resonant frequency for this string is

Discussion

18.	A spring block system is doing SHM with Amplitude A and angular frequency ω. At t=T, the particle is at extreme position. Write displacement versus time equation.
Answer» A spring block system is doing SHM with Amplitude A and angular frequency $ω$ . At t=T, the particle is at extreme position. Write displacement versus time equation.

18.

A spring block system is doing SHM with Amplitude A and angular frequency ω. At t=T, the particle is at extreme position. Write displacement versus time equation.

Answer»

A spring block system is doing SHM with Amplitude A and angular frequency $ω$ .

At t=T, the particle is at extreme position. Write displacement versus time equation.

Discussion

19.	Three samples A, B and C of the same gas (γ=1.5) have equal volumes and temperatures. The volu me of each sample is doubled, the process being isother mal for A, adiabatic for B and isobaric for C. If the final pressures are equal for the three samples, Find the ratio of the initial pressures.
Answer» Three samples A, B and C of the same gas ( $γ = 1.5)$ have equal volumes and temperatures. The volu me of each sample is doubled, the process being isother mal for A, adiabatic for B and isobaric for C. If the final pressures are equal for the three samples, Find the ratio of the initial pressures.

Discussion

20.	Two pendula start swinging simultaneously. By the time the first pendulum makes 20 oscillations, 2nd pendulum makes 15 oscillations. The ratio of their lengths is:
Answer» Two pendula start swinging simultaneously. By the time the first pendulum makes 20 oscillations, $2^{n d}$ pendulum makes 15 oscillations. The ratio of their lengths is:

Discussion

21.	A wooden block of mass 0.5 kg and density 800 kg m−3 is fastened to the free end of a vertical spring of spring constant 50 N m−1 fixed at the bottom.If the entire system is completely immersed in water, find (a) the elongation (or compression) of the spring in equilibrium and (b) the time -period of vertical oscillations of the block when it is slightly depressed and released
Answer» A wooden block of mass 0.5 kg and density 800 kg $m^{- 3}$ is fastened to the free end of a vertical spring of spring constant 50 N $m^{- 1}$ fixed at the bottom.If the entire system is completely immersed in water, find (a) the elongation (or compression) of the spring in equilibrium and (b) the time -period of vertical oscillations of the block when it is slightly depressed and released

Discussion

22.	Water enters through end A with speed v1 and leaves through end B with speed v2 of a cylindrical tube AB. The tube is always completely filled with water. In case I tube is horizontal and in case II it is vertical with end A upwards and in case III it is vertical with end B upwards. We have v1=v2 for
Answer» Water enters through end A with speed $v_{1}$ and leaves through end B with speed $v_{2}$ of a cylindrical tube AB. The tube is always completely filled with water. In case I tube is horizontal and in case II it is vertical with end A upwards and in case III it is vertical with end B upwards. We have $v_{1} = v_{2}$ for

Discussion

23.	If ϵ0 and μ0 are the permittivity and permeability of free space and ϵ and μ are the corresponding quantities for a medium, Then refractive index of the medium is
Answer» If $ϵ_{0} a n d μ_{0}$ are the permittivity and permeability of free space and $ϵ a n d μ$ are the corresponding quantities for a medium, Then refractive index of the medium is

Discussion

24.	A ball is projected down the incline plane with velocity u at right angle to the plane which is inclined at an angle α with the horizontal. The distance x along the inclined plane that it will travel before again striking the slope is
Answer» A ball is projected down the incline plane with velocity $u$ at right angle to the plane which is inclined at an angle $α$ with the horizontal. The distance $x$ along the inclined plane that it will travel before again striking the slope is

Discussion

25.	A force →F=3^i+2^j−4^k acts at the point (1,−1,2). Find its torque about the point (2,−1,3).
Answer» A force $\to F = 3^i + 2^j - 4^k$ acts at the point $(1, - 1, 2)$ . Find its torque about the point $(2, - 1, 3) .$

Discussion

26.	A bead of mass 10 g oscillates along the horizontal diameter AB of the ring of radius R=5 cm. At an instant shown in the figure, kinetic energy of the particle is 0.015 J. Find the force applied (in Newtons) by the ring on the bead.
Answer» A bead of mass $10 g$ oscillates along the horizontal diameter $A B$ of the ring of radius $R = 5 cm$ . At an instant shown in the figure, kinetic energy of the particle is $0.015 J$ . Find the force applied $(in Newtons)$ by the ring on the bead.

Discussion

27.	Two cars moving in opposite directions approach each other with speed of 22 m/s and 16.5 m/s respectively. The driver of the first car blows a horn having a frequency 400 Hz. The frequency heard by the driver of the second car is (Take velocity of sound 340 m/s)
Answer» Two cars moving in opposite directions approach each other with speed of $22 m / s$ and $16.5 m / s$ respectively. The driver of the first car blows a horn having a frequency $400 H z$ . The frequency heard by the driver of the second car is (Take velocity of sound $340 m / s$ )

Discussion

28.	White light is used to illuminate the two slits in YDSE. The separation between the slits is b and the screen is at a distance d (>>b) from the slits. At a point on the screen directly in front of one of the slits, certain wavelengths are missing. Some of these missing wavelengths are
Answer» White light is used to illuminate the two slits in YDSE. The separation between the slits is b and the screen is at a distance d (>>b) from the slits. At a point on the screen directly in front of one of the slits, certain wavelengths are missing. Some of these missing wavelengths are

Discussion

29.	Find the change in the volume of 1.0 litre kerosene when it is subjected to an extra pressure of 2.0 x 105 N m−2 from the following data. Density of kerosene = 800 kg m−3 and speed of sound in kerosene = 1330 m s−1.
Answer» Find the change in the volume of 1.0 litre kerosene when it is subjected to an extra pressure of 2.0 x 10 $^{5}$ N m $^{- 2}$ from the following data. Density of kerosene = 800 kg m $^{- 3}$ and speed of sound in kerosene = 1330 m s $^{- 1}$ .

Discussion

30.	A solid cylinder of height h and mass m floats in a liquid of density ρ as shown in Fig. Now the cylinder is released inside a liquid of density ρ4, contained in a downward accelerated vessel. Determine the magnitude of acceleration of vessel(A), for which cylinder sinks with relative acceleration A3 with respect to vessel. Neglect any dissipative force:
Answer» A solid cylinder of height h and mass m floats in a liquid of density $ρ$ as shown in Fig. Now the cylinder is released inside a liquid of density $\frac{ρ}{4}$ , contained in a downward accelerated vessel. Determine the magnitude of acceleration of vessel(A), for which cylinder sinks with relative acceleration $\frac{A}{3}$ with respect to vessel. Neglect any dissipative force:

30.

A solid cylinder of height h and mass m floats in a liquid of density ρ as shown in Fig. Now the cylinder is released inside a liquid of density ρ4, contained in a downward accelerated vessel. Determine the magnitude of acceleration of vessel(A), for which cylinder sinks with relative acceleration A3 with respect to vessel. Neglect any dissipative force:

Answer»

A solid cylinder of height h and mass m floats in a liquid of density $ρ$ as shown in Fig. Now the cylinder is released inside a liquid of density $\frac{ρ}{4}$ , contained in a downward accelerated vessel. Determine the magnitude of acceleration of vessel(A), for which cylinder sinks with relative acceleration $\frac{A}{3}$ with respect to vessel.
Neglect any dissipative force:

Discussion

31.	A steel rod of length 1 m is heated from 25∘C to 75∘C keeping its length constant. The longitudinal strain developed in the rod is (Given: Coefficient of linear expansion of steel =12×10−6/∘C) n×10−4 . Report n.
Answer» A steel rod of length 1 m is heated from $25^{\circ} C$ to $75^{\circ} C$ keeping its length constant. The longitudinal strain developed in the rod is (Given: Coefficient of linear expansion of steel $= 12 \times 10^{- 6} /^{\circ} C) n \times 10^{- 4}$ . Report n.

Discussion

32.	For shown situation, initially the blocks are at rest and spring is unstretched. Find the maximum elongation in the spring. Neglect friction everywhere. Here spring constant is K.
Answer» For shown situation, initially the blocks are at rest and spring is unstretched. Find the maximum elongation in the spring. Neglect friction everywhere. Here spring constant is $K .$

Discussion

33.	Ajit had a high tension tower erected on his farm land. He kept complaining to the authorities to remove it as it was occupying a large portion of his land. His uncle, who was a teacher, explained to him the need for erecting these towers for efficient transmission of power. As Ajit realised its significance, he stopped complaining. Answer the following questions: (a) Why is it necessary to transport power at high voltage? (b) A low power factor implies large power loss. Explain. (c) Write two values each displayed by Ajit and his uncle
Answer» Ajit had a high tension tower erected on his farm land. He kept complaining to the authorities to remove it as it was occupying a large portion of his land. His uncle, who was a teacher, explained to him the need for erecting these towers for efficient transmission of power. As Ajit realised its significance, he stopped complaining. Answer the following questions: (a) Why is it necessary to transport power at high voltage? (b) A low power factor implies large power loss. Explain. (c) Write two values each displayed by Ajit and his uncle

33.

Ajit had a high tension tower erected on his farm land. He kept complaining to the authorities to remove it as it was occupying a large portion of his land. His uncle, who was a teacher, explained to him the need for erecting these towers for efficient transmission of power. As Ajit realised its significance, he stopped complaining. Answer the following questions: (a) Why is it necessary to transport power at high voltage? (b) A low power factor implies large power loss. Explain. (c) Write two values each displayed by Ajit and his uncle

Answer»

Ajit had a high tension tower erected on his farm land. He kept complaining to the authorities to remove it as it was occupying a large portion of his land. His uncle, who was a teacher, explained to him the need for erecting these towers for efficient transmission of power. As Ajit realised its significance, he stopped complaining. Answer the following questions:

(a) Why is it necessary to transport power at high voltage?

(b) A low power factor implies large power loss. Explain.

(c) Write two values each displayed by Ajit and his uncle

Discussion

34.	Two carnot engines are connected in series with a common intermediate reservoir and output work of both engines is same. If temperature of source of 1st engine is at 600 K and temperature of sink of 2nd engine is at 400 K. The temperature of intermediate reservoir will be
Answer» Two carnot engines are connected in series with a common intermediate reservoir and output work of both engines is same. If temperature of source of $1^{s t}$ engine is at $600 K$ and temperature of sink of $2^{n d}$ engine is at $400 K$ . The temperature of intermediate reservoir will be

Discussion

35.	If the value of atmospheric pressure is 106dyne cm−2, then its value in SI units is:
Answer» If the value of atmospheric pressure is $10^{6} d y n e c m^{- 2}$ , then its value in SI units is:

Discussion

36.	A wire carrying current I is laid in shape of a curve which is represented in plane polar coordinate system as, r=b+cπθ for 0≤θ≤π2 Here b and c are positive constants. θ is the angle measured with respect to positive X direction in anticlockwise sense and r is the distance from origin (see figure). The magnetic field at the origin due to the wire is found to be μoIxcln(1+cyb) The value of xy is
Answer» A wire carrying current $I$ is laid in shape of a curve which is represented in plane polar coordinate system as, $r = b + \frac{c}{π} θ f o r 0 \leq θ \leq \frac{π}{2}$ Here $b$ and $c$ are positive constants. $θ$ is the angle measured with respect to positive $X$ direction in anticlockwise sense and $r$ is the distance from origin (see figure). The magnetic field at the origin due to the wire is found to be $\frac{μ_{o} I}{x c} l n (1 + \frac{c}{y b})$ The value of xy is

Discussion

37.	A ball is projected from ground with a speed of 30 m/s , find θ so that ball passes through point A. (g=10 ms−2)
Answer» A ball is projected from ground with a speed of 30 m/s , find $θ$ so that ball passes through point A. $(g = 10 m s^{- 2})$

Discussion

38.	A current i is uniformly disturbed over the cross section of a cylindrical conductor of radius R. The magnetic flux through the shaded rectangular plane which passes through the axis due to the long straight current is
Answer» A current i is uniformly disturbed over the cross section of a cylindrical conductor of radius R. The magnetic flux through the shaded rectangular plane which passes through the axis due to the long straight current is

Discussion

39.	An engine generates a power of 75 kW having efficiency of 80% and the car moves with a constant velocity of 20 m/s. Find the force generated by the engine. (Assume the engine applies a constant force on the car)
Answer» An engine generates a power of $75 kW$ having efficiency of $80 %$ and the car moves with a constant velocity of $20 m/s$ . Find the force generated by the engine. (Assume the engine applies a constant force on the car)

Discussion

40.	The transformed equation of 3x2+4xy−7y2−14=0 when origin is shifted to the point (−1,2), and then axes being rotated at an angle of 90∘ is
Answer» The transformed equation of $3 x^{2} + 4 x y - 7 y^{2} - 14 = 0$ when origin is shifted to the point $(- 1, 2)$ , and then axes being rotated at an angle of $90^{\circ}$ is

Discussion

41.	The maximum range for a shell fired by a cannon on horizontal terrain is 20 km. What must be the muzzle velocity of the shell? (Take g=10 m/s2)
Answer» The maximum range for a shell fired by a cannon on horizontal terrain is $20 km$ . What must be the muzzle velocity of the shell? (Take $g = 10 {m/s}^{2}$ )

Discussion

42.	A machine gun fires a bullet of mass 40 g with a velocity of 1200ms−1. The gun can exert a maximum force of 144 N on the bullet. How many bullets can he fire per second at the most?
Answer» A machine gun fires a bullet of mass 40 g with a velocity of $1200 m s^{- 1}$ . The gun can exert a maximum force of 144 N on the bullet. How many bullets can he fire per second at the most?

Discussion

43.	Weighing machine measure what mass or weight of human body?
Answer» Weighing machine measure what mass or weight of human body?

Discussion

44.	The work done in blowing a soap bubble of 10 cm radius is - (surface tension of soap =0.03 N/m).
Answer» The work done in blowing a soap bubble of $10 cm$ radius is - (surface tension of soap $= 0.03 N/m$ ).

Discussion

45.	A block of mass 1 kg is placed at the point A of a rough track shown in figure (8-E6). If slightly pushed towards right, it stops at the point .8 of the track. Calculate the work done by the frictional force on the block during its transit from A to B.
Answer» A block of mass 1 kg is placed at the point A of a rough track shown in figure (8-E6). If slightly pushed towards right, it stops at the point .8 of the track. Calculate the work done by the frictional force on the block during its transit from A to B.

45.

A block of mass 1 kg is placed at the point A of a rough track shown in figure (8-E6). If slightly pushed towards right, it stops at the point .8 of the track. Calculate the work done by the frictional force on the block during its transit from A to B.

Answer»

A block of mass 1 kg is placed at the point A of a rough track shown in figure (8-E6). If slightly pushed towards right, it stops at the point .8 of the track. Calculate the work done by the frictional force on the block during its transit from A to B.

Discussion

46.	A projectile is given an initial velocity of (^i+2^j)m/s, where ^i is along the ground and ^j is along the vertical. If g=10m/s2 the equation of its trajectory is:
Answer» A projectile is given an initial velocity of $(^i + 2^j) m / s$ , where $^i$ is along the ground and $^j$ is along the vertical. If $g = 10 m / s^{2}$ the equation of its trajectory is:

Discussion

47.	Electric charges of 1 μC,−1 μC and 2 μC are placed in air at the corners A,B and C of an equilateral triangle having length of each side 10 cm respectively. The resultant force on the charge at C is
Answer» Electric charges of $1 μ C, - 1 μ C$ and $2 μ C$ are placed in air at the corners $A, B$ and $C$ of an equilateral triangle having length of each side $10 c m$ respectively. The resultant force on the charge at $C$ is

Discussion

48.	Air column in a tube dipped in water vibrates in its fundamental mode. If water is replaced by an oil of higher density, then its frequency will
Answer» Air column in a tube dipped in water vibrates in its fundamental mode. If water is replaced by an oil of higher density, then its frequency will

Discussion

49.	Two balls are fastened to two light strings of same length of l and of different masses m and 2m as shown in the figure. The other end of the strings are fixed at O. The strings are kept in the same horizontal line and the system is released from rest. The collision between the balls is perfectly elastic. Find the ratio of the speeds of the balls, just after the collision.
Answer» Two balls are fastened to two light strings of same length of $l$ and of different masses $m$ and $2 m$ as shown in the figure. The other end of the strings are fixed at $O$ . The strings are kept in the same horizontal line and the system is released from rest. The collision between the balls is perfectly elastic. Find the ratio of the speeds of the balls, just after the collision.

Discussion

50.	In the figure shown, there is no friction between B and ground & μ=23 between A and B; then:
Answer» In the figure shown, there is no friction between B and ground & $μ = \frac{2}{3}$ between A and B; then:

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

Gases show positive deviations when:

The speed of transverse waves on a string depends upon

A 50 g bullet moving with velocity 10 m/s strikes a block of mass 950 g at rest and gets embedded in it. The loss in kinetic energy will be

What is the Reaumur temperature scale? Give the advantage and disadvantage of Reaumur scale thermometer.

If black wire of platinum is heated, then its colour first appear red, then yellow and finally white. It can be understood on the basis of

If the velocity of sound in air is 350 m/s. Then the fundamental frequency of an open organ pipe of length 50 cm, will be

A body released from a height h takes time t to reach earth’s surface. The time taken by the same body released from the same height to reach the moon’s surface is

An object of mass M is kept on a rough table as seen from above. Forces are applied as shown. Find the direction (from the vertical) of static friction if the object does not move.

If a hole is bored along the diameter of the earth and a stone is dropped into hole

Ship A is sailing towards north-east with velocity →v=30^i+50^j km/hr where ^i points east and ^j towards north. Ship B is at a distance of 80 km east and 150 km north of Ship A and is sailing towards west at 10 km/hr. Time in which A will be at minimum distance from B is

Which of the following results is true?

Two putty balls of equal mass moving with equal velocity in mutually perpendicular directions, stick together after collision. If the balls were initially moving with a velocity of 45√2 ms−1 each, the velocity of their combined mass after collision is

Two balls are projected from the same point in directions inclined at 600 and 300 to the horizontal. If they attain the same height, the ratio of their velocity of projection would be (g = 9.8 ms−2).

A remote-sensing satellite of earth revolves in a circular orbit at a height of 0.25×106 m above the surface of earth. If earth's radius is 6.4×106 m and g=9.8 ms−2, then the orbital speed of the satellite is

A string is stretched between fixed points separated by 75.0 cm. It is observed to have resonant frequencies of 420 Hz and 315 Hz. There are no other resonant frequencies between these two. The lowest resonant frequency for this string is

A spring block system is doing SHM with Amplitude A and angular frequency ω. At t=T, the particle is at extreme position. Write displacement versus time equation.

Three samples A, B and C of the same gas (γ=1.5) have equal volumes and temperatures. The volu me of each sample is doubled, the process being isother mal for A, adiabatic for B and isobaric for C. If the final pressures are equal for the three samples, Find the ratio of the initial pressures.

Two pendula start swinging simultaneously. By the time the first pendulum makes 20 oscillations, 2nd pendulum makes 15 oscillations. The ratio of their lengths is:

If ϵ0 and μ0 are the permittivity and permeability of free space and ϵ and μ are the corresponding quantities for a medium, Then refractive index of the medium is

A ball is projected down the incline plane with velocity u at right angle to the plane which is inclined at an angle α with the horizontal. The distance x along the inclined plane that it will travel before again striking the slope is

A force →F=3^i+2^j−4^k acts at the point (1,−1,2). Find its torque about the point (2,−1,3).

A bead of mass 10 g oscillates along the horizontal diameter AB of the ring of radius R=5 cm. At an instant shown in the figure, kinetic energy of the particle is 0.015 J. Find the force applied (in Newtons) by the ring on the bead.

Two cars moving in opposite directions approach each other with speed of 22 m/s and 16.5 m/s respectively. The driver of the first car blows a horn having a frequency 400 Hz. The frequency heard by the driver of the second car is (Take velocity of sound 340 m/s)

White light is used to illuminate the two slits in YDSE. The separation between the slits is b and the screen is at a distance d (&gt;&gt;b) from the slits. At a point on the screen directly in front of one of the slits, certain wavelengths are missing. Some of these missing wavelengths are

Find the change in the volume of 1.0 litre kerosene when it is subjected to an extra pressure of 2.0 x 105 N m−2 from the following data. Density of kerosene = 800 kg m−3 and speed of sound in kerosene = 1330 m s−1.

A steel rod of length 1 m is heated from 25∘C to 75∘C keeping its length constant. The longitudinal strain developed in the rod is (Given: Coefficient of linear expansion of steel =12×10−6/∘C) n×10−4 . Report n.

For shown situation, initially the blocks are at rest and spring is unstretched. Find the maximum elongation in the spring. Neglect friction everywhere. Here spring constant is K.

Two carnot engines are connected in series with a common intermediate reservoir and output work of both engines is same. If temperature of source of 1st engine is at 600 K and temperature of sink of 2nd engine is at 400 K. The temperature of intermediate reservoir will be

If the value of atmospheric pressure is 106dyne cm−2, then its value in SI units is:

A ball is projected from ground with a speed of 30 m/s , find θ so that ball passes through point A. (g=10 ms−2)

A current i is uniformly disturbed over the cross section of a cylindrical conductor of radius R. The magnetic flux through the shaded rectangular plane which passes through the axis due to the long straight current is

An engine generates a power of 75 kW having efficiency of 80% and the car moves with a constant velocity of 20 m/s. Find the force generated by the engine. (Assume the engine applies a constant force on the car)

The transformed equation of 3x2+4xy−7y2−14=0 when origin is shifted to the point (−1,2), and then axes being rotated at an angle of 90∘ is

The maximum range for a shell fired by a cannon on horizontal terrain is 20 km. What must be the muzzle velocity of the shell? (Take g=10 m/s2)

A machine gun fires a bullet of mass 40 g with a velocity of 1200ms−1. The gun can exert a maximum force of 144 N on the bullet. How many bullets can he fire per second at the most?

Weighing machine measure what mass or weight of human body?

The work done in blowing a soap bubble of 10 cm radius is - (surface tension of soap =0.03 N/m).

A block of mass 1 kg is placed at the point A of a rough track shown in figure (8-E6). If slightly pushed towards right, it stops at the point .8 of the track. Calculate the work done by the frictional force on the block during its transit from A to B.

A projectile is given an initial velocity of (^i+2^j)m/s, where ^i is along the ground and ^j is along the vertical. If g=10m/s2 the equation of its trajectory is:

Electric charges of 1 μC,−1 μC and 2 μC are placed in air at the corners A,B and C of an equilateral triangle having length of each side 10 cm respectively. The resultant force on the charge at C is

Air column in a tube dipped in water vibrates in its fundamental mode. If water is replaced by an oil of higher density, then its frequency will

In the figure shown, there is no friction between B and ground &amp; μ=23 between A and B; then:

White light is used to illuminate the two slits in YDSE. The separation between the slits is b and the screen is at a distance d (>>b) from the slits. At a point on the screen directly in front of one of the slits, certain wavelengths are missing. Some of these missing wavelengths are

In the figure shown, there is no friction between B and ground & μ=23 between A and B; then: