50278 + Interview Questions in Physics

1.	If the mass of the body A is m. Find the mass of the body B in terms of mass of the body A for the system to be in equilibrium.
Answer» If the mass of the body $A$ is $m$ . Find the mass of the body $B$ in terms of mass of the body $A$ for the system to be in equilibrium.

Discussion

2.	In the system shown, mass of block A, B and C are mA=4m, mB=3m and mC=8m. If the system is released from rest, find the acceleration of block B. Assume all surfaces to be smooth and string inextensible.
Answer» In the system shown, mass of block A, B and C are $m_{A} = 4 m, m_{B} = 3 m$ and $m_{C} = 8 m$ . If the system is released from rest, find the acceleration of block $B$ . Assume all surfaces to be smooth and string inextensible.

Discussion

3.	A non-planar loop of conducting wire carrying a current I is placed as shown in the figure. Each of the straight sections of the loop is of length 2a. The magnetic field due to this loop at the point P (a, 0, a) points in the direction
Answer» A non-planar loop of conducting wire carrying a current $I$ is placed as shown in the figure. Each of the straight sections of the loop is of length 2a. The magnetic field due to this loop at the point P (a, 0, a) points in the direction

Discussion

4.	In Young’s double slit experiment, the slits are horizontal. The intensity at a point P as shown in figure is 34I0, where I0 is the maximum intensity. Then the value of θ is
Answer» In Young’s double slit experiment, the slits are horizontal. The intensity at a point P as shown in figure is $\frac{3}{4} I_{0}$ , where $I_{0}$ is the maximum intensity. Then the value of $θ$ is

4.

In Young’s double slit experiment, the slits are horizontal. The intensity at a point P as shown in figure is 34I0, where I0 is the maximum intensity. Then the value of θ is

Answer»

In Young’s double slit experiment, the slits are horizontal. The intensity at a point P as shown in figure is $\frac{3}{4} I_{0}$ , where $I_{0}$ is the maximum intensity. Then the value of $θ$ is

Discussion

5.	The force F required to extend a rubber wire by a length x from its natural length was found to vary as in diagram. The energy stored in the rubber for an extension of 5 m is
Answer» The force F required to extend a rubber wire by a length $x$ from its natural length was found to vary as in diagram. The energy stored in the rubber for an extension of 5 m is

5.

The force F required to extend a rubber wire by a length x from its natural length was found to vary as in diagram. The energy stored in the rubber for an extension of 5 m is

Answer»

The force F required to extend a rubber wire by a length $x$ from its natural length was found to vary as in diagram. The energy stored in the rubber for an extension of 5 m is

Discussion

6.	A conducting tube is passing through a bath. A liquid at temperature 90∘C and specific heat s is entering at one end of tube. The rate of flow of liquid is 1kg/s and exit temperature is 50∘C. In bath another liquid having specific heat 2s and inlet temperature 20∘C is entering at a rate of 2kg/s. If the exit temperature of liquid coming out of the bath is 10x. Find x (Assume steady-state condition) ___
Answer» A conducting tube is passing through a bath. A liquid at temperature $90^{\circ} C$ and specific heat s is entering at one end of tube. The rate of flow of liquid is 1kg/s and exit temperature is $50^{\circ} C$ . In bath another liquid having specific heat 2s and inlet temperature $20^{\circ} C$ is entering at a rate of 2kg/s. If the exit temperature of liquid coming out of the bath is 10x. Find x (Assume steady-state condition) ___

Discussion

7.	A layer of benzene floats on water. If the angle of incidence of the light entering benzene from air is 60∘, then the angle that light makes with normal in water is (Refractive index of water =43)
Answer» A layer of benzene floats on water. If the angle of incidence of the light entering benzene from air is $60^{\circ}$ , then the angle that light makes with normal in water is (Refractive index of water $= \frac{4}{3}$ )

7.

A layer of benzene floats on water. If the angle of incidence of the light entering benzene from air is 60∘, then the angle that light makes with normal in water is (Refractive index of water =43)

Answer»

A layer of benzene floats on water. If the angle of incidence of the light entering benzene from air is $60^{\circ}$ , then the angle that light makes with normal in water is (Refractive index of water $= \frac{4}{3}$ )

Discussion

8.	Sound of wavelength λ passes through a Quincke’s tube, which is adjusted to give a maximum intensity I0. Through what distance should the sliding tube be moved to give an intensity I02?
Answer» Sound of wavelength $λ$ passes through a Quincke’s tube, which is adjusted to give a maximum intensity $I_{0}$ . Through what distance should the sliding tube be moved to give an intensity $\frac{I_{0}}{2}$ ?

Discussion

9.	A gun is mounted on a plateau 960 m away from it’s edge as shown. Height of plateau is 960 m. The gun can fire shells with a velocity of 100 m/s at any angle. Of the following choices, what is the minimum distance (OP)x from the edge of plateau where the shell of gun can reach?
Answer» A gun is mounted on a plateau $960 m$ away from it’s edge as shown. Height of plateau is $960 m$ . The gun can fire shells with a velocity of $100 m/s$ at any angle. Of the following choices, what is the minimum distance $(O P) x$ from the edge of plateau where the shell of gun can reach?

Discussion

10.	A continuous flow water heater (geyser) has an electrical power rating =2 kW and efficiency of conversion of electrical power into heat =80%. If water is flowing through the device at the rate of 100 cc/sec, and the inlet temperature is 10∘C, the outlet temperature will be
Answer» A continuous flow water heater (geyser) has an electrical power rating $= 2 kW$ and efficiency of conversion of electrical power into heat $= 80 %$ . If water is flowing through the device at the rate of $100 cc/sec$ , and the inlet temperature is $10^{\circ} C$ , the outlet temperature will be

Discussion

11.	When forces F1,F2,F3 are acting on a particle of mass m such that F2 and F3 are mutually perpendicular, then the particle remains stationary. If the force F1 is now removed then the magnitude of acceleration of the particle is
Answer» When forces $F_{1}, F_{2}, F_{3}$ are acting on a particle of mass $m$ such that $F_{2}$ and $F_{3}$ are mutually perpendicular, then the particle remains stationary. If the force $F_{1}$ is now removed then the magnitude of acceleration of the particle is

Discussion

12.	The elevator shown in figure is descending with an acceleration of 2m/s2. The mass of the block A is 0.5 kg. What force is exerted by the block a on the block B ?
Answer» The elevator shown in figure is descending with an acceleration of $2 m / s^{2}$ . The mass of the block A is 0.5 kg. What force is exerted by the block a on the block B ?

12.

The elevator shown in figure is descending with an acceleration of 2m/s2. The mass of the block A is 0.5 kg. What force is exerted by the block a on the block B ?

Answer»

The elevator shown in figure is descending with an acceleration of $2 m / s^{2}$ . The mass of the block A is 0.5 kg. What force is exerted by the block a on the block B ?

Discussion

13.	A bullet leaving the muzzle of a rifle barel with a velocity v penetrates a plank and loses one 15th of its velocity. It then strikes second plank, which it just penetrates through. Find out the ratio of the thickness of the planks. [Supposing the average resistance to the penetration is same in both the case]
Answer» A bullet leaving the muzzle of a rifle barel with a velocity $v$ penetrates a plank and loses one ${\frac{1}{5}}^{t h}$ of its velocity. It then strikes second plank, which it just penetrates through. Find out the ratio of the thickness of the planks. [Supposing the average resistance to the penetration is same in both the case]

Discussion

14.	An image 23 the size of the object is formed by a convex lens at a distance of 12 cm from it. Find the focal length of the lens.
Answer» An image $\frac{2}{3}$ the size of the object is formed by a convex lens at a distance of 12 cm from it. Find the focal length of the lens.

Discussion

15.	An infinite line charge produces an electric field of 9×104 NC−1 at a distance of 2 cm. Calculate the linear charge density.
Answer» An infinite line charge produces an electric field of $9 \times 10^{4} N C^{- 1}$ at a distance of 2 cm. Calculate the linear charge density.

Discussion

16.	Three blocks of masses m1, m2 and m3 are connected by massless strings as shown in the figure and placed on a frictionless table. A force of 40 N pulls the system. Then calculate the value of T (in N) if m1=10 kg,m2=6 kg and m3=4 kg.
Answer» Three blocks of masses $m_{1}$ , $m_{2}$ and $m_{3}$ are connected by massless strings as shown in the figure and placed on a frictionless table. A force of $40 N$ pulls the system. Then calculate the value of $T$ (in $N$ ) if $m_{1} = 10 k g, m_{2} = 6 k g$ and $m_{3} = 4 k g$ .

Discussion

17.	A particle moves with deceleration along the circle of radius R so that at any moment of time its tangential and centripetal accelerations are equal in moduli. At the initial moment t=0, the speed of the particle equals v0. Then The total acceleration of the particle is
Answer» A particle moves with deceleration along the circle of radius $R$ so that at any moment of time its tangential and centripetal accelerations are equal in moduli. At the initial moment $t = 0$ , the speed of the particle equals $v_{0}$ . Then The total acceleration of the particle is

Discussion

18.	When 100 V dc is applied across a coil, a current of one ampere flows through it, but when 100 V ac of 50 Hz is applied to the same coil, only 0.5 amp flows. Calculate the resistance and inductance of the coil.
Answer» When $100 V dc$ is applied across a coil, a current of one ampere flows through it, but when $100 V ac$ of $50 Hz$ is applied to the same coil, only $0.5 amp$ flows. Calculate the resistance and inductance of the coil.

Discussion

19.	A parallelogram has diagonals expressed as →A=5^i−4^j+3^k and →B=3^i+2^j−^k. Area of parallelogram is
Answer» A parallelogram has diagonals expressed as $\to A = 5^i - 4^j + 3^k$ and $\to B = 3^i + 2^j -^k$ . Area of parallelogram is

Discussion

20.	Two smooth cylindrical bars weighing W each, lie next to each other in contact. A similar third bar is placed over the two bars as shown in figure. Neglecting friction, the minimum horizontal force on each lower bar necessary to keep them together is
Answer» Two smooth cylindrical bars weighing $W$ each, lie next to each other in contact. A similar third bar is placed over the two bars as shown in figure. Neglecting friction, the minimum horizontal force on each lower bar necessary to keep them together is

Discussion

21.	What are the physical quantities on which vectors and scalers are differentiated?
Answer» What are the physical quantities on which vectors and scalers are differentiated?

Discussion

22.	Show that the vectors 2^i−3^j+4^k and −4^i+6^j−8^k are collinear.
Answer» Show that the vectors $2^i - 3^j + 4^k a n d - 4^i + 6^j - 8^k$ are collinear.

Discussion

23.	A train starts from rest and its speed increases at a constant rate α to v and then remains constant for an interval and finally decreases to zero at a constant rate β. The total distance travelled by train is l. The time taken to complete the journey is t. Then,
Answer» A train starts from rest and its speed increases at a constant rate $α$ to $v$ and then remains constant for an interval and finally decreases to zero at a constant rate $β$ . The total distance travelled by train is $l$ . The time taken to complete the journey is $t$ . Then,

Discussion

24.	What is the relative velocity when two bodies move in opposite direction?
Answer» What is the relative velocity when two bodies move in opposite direction?

Discussion

25.	In the arrangement shown, the rod is freely pivoted at point O and is in contact with the equilateral triangular block which can move on the horizontal frictionless ground. As the block is given a speed v in the forward direction, the rod rotates about point O. Find the angular velocity of the rod in rad/s at the instant when θ=30∘. [Take v=20 m/s, a=1 m]
Answer» In the arrangement shown, the rod is freely pivoted at point O and is in contact with the equilateral triangular block which can move on the horizontal frictionless ground. As the block is given a speed $v$ in the forward direction, the rod rotates about point O. Find the angular velocity of the rod in rad/s at the instant when $θ = 30^{\circ}$ . [Take $v = 20 m/s$ , $a = 1 m$ ]

Discussion

26.	Find the approximate change in the volume V of a cube of side x metre caused by increasing the side by 1%.
Answer» Find the approximate change in the volume V of a cube of side x metre caused by increasing the side by 1%.

Discussion

27.	A solid sphere of mass 0.50 kg is kept at rest on horizontal surface. The coefficient of static friction between the solid sphere and the surface in contact is 27. The maximum force that can be applied at the highest point of sphere in the horizontal direction so that the sphere dosen't slip on the surface is given by x3 N, then value of x is (Assume g=10 ms−2)
Answer» A solid sphere of mass $0.50 kg$ is kept at rest on horizontal surface. The coefficient of static friction between the solid sphere and the surface in contact is $\frac{2}{7}$ . The maximum force that can be applied at the highest point of sphere in the horizontal direction so that the sphere dosen't slip on the surface is given by $\frac{x}{3} N$ , then value of $x$ is (Assume $g = 10 {ms}^{- 2}$ )

Discussion

28.	The molar heat capacity of oxygen gas is given by the expression Cv=a+bT+cT2 where a, b and c are constants. What will be the change in the internal energy of 8 g of oxygen, if it is heated from 200 K to 300 K at constant volume? Assume oxygen to be an ideal gas. (Given, a=1.2 JK−1mol−1, b=12.8×10−2JK−2mol−1, c=1.0×10−7JK−3mol−1).
Answer» The molar heat capacity of oxygen gas is given by the expression $C_{v} = a + b T + c T^{2}$ where a, b and c are constants. What will be the change in the internal energy of 8 g of oxygen, if it is heated from 200 K to 300 K at constant volume? Assume oxygen to be an ideal gas. (Given, $a = 1.2 J K^{- 1} m o l^{- 1}$ , $b = 12.8 \times 10^{- 2} J K^{- 2} m o l^{- 1}$ , $c = 1.0 \times 10^{- 7} J K^{- 3} m o l^{- 1}$ ).

Discussion

29.	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 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 origin varies as?

Discussion

30.	Why does magnetic field increases the resistivity of all metals except iron , cobalt and nickel ?
Answer» Why does magnetic field increases the resistivity of all metals except iron , cobalt and nickel ?

Discussion

31.	An ideal monoatomic gas is taken round the cycle ABCA as shown in the Fig. 17.9 The work done during the cycle is
Answer» An ideal monoatomic gas is taken round the cycle ABCA as shown in the Fig. 17.9 The work done during the cycle is

Discussion

32.	A disc rotating about its axis with angular speed ω0 is placed lightly (without any translational push) on a perfectly frictionless table. The radius of the disc is R. What are the linear velocities of the points A, B and C on the disc shown in Fig. 7.41? Will the disc roll in the direction indicated?
Answer» A disc rotating about its axis with angular speed $ω_{0}$ is placed lightly (without any translational push) on a perfectly frictionless table. The radius of the disc is R. What are the linear velocities of the points A, B and C on the disc shown in Fig. 7.41? Will the disc roll in the direction indicated?

Discussion

33.	A body is dropped from a certain height h (h is very large) and second body is thrown downward from the same height h with velocity of 5 m/s simultaneously. What will be difference in heights of the two bodies after 3s ?
Answer» A body is dropped from a certain height $h$ ( $h$ is very large) and second body is thrown downward from the same height $h$ with velocity of $5 m/s$ simultaneously. What will be difference in heights of the two bodies after $3 s$ ?

Discussion

34.	Q. A lamp is connected in series with a capacitor . Predict your observations when the system is connected first across a DC and then an AC source . What happens if the capacitance of the capacitor is reduced ?
Answer» Q. A lamp is connected in series with a capacitor . Predict your observations when the system is connected first across a DC and then an AC source . What happens if the capacitance of the capacitor is reduced ?

Discussion

35.	A block of mass 5 kg is lying on a rough horizontal surface. The coefficients of static and kinetic friction between the block and the surface respectively are 0.7 and 0.5. A horizontal force just sufficient to move the block is applied to it. If the force continues to act even after the block has started moving, what will be the acceleration of the block? Take g=10 ms−2.
Answer» A block of mass 5 kg is lying on a rough horizontal surface. The coefficients of static and kinetic friction between the block and the surface respectively are 0.7 and 0.5. A horizontal force just sufficient to move the block is applied to it. If the force continues to act even after the block has started moving, what will be the acceleration of the block? Take $g = 10 m s^{- 2}$ .

Discussion

36.	Which of the following doesn't use the application of Conservation of Angular Momentum?
Answer» Which of the following doesn't use the application of Conservation of Angular Momentum?

Discussion

37.	A uniform magnetic field B is set up along the positive X-axis. A particle of charge `q' and mass 'm' moving with a velocity v enters the field at the origin in X-Y plane such that it has velocity components both along and perpendicular to the magnetic field B. Trace, giving reason, the trajectory followed by the particle. Find out the expression for the distance moved by the particle along the magnetic field in one rotation.
Answer» A uniform magnetic field B is set up along the positive X-axis. A particle of charge `q' and mass 'm' moving with a velocity v enters the field at the origin in X-Y plane such that it has velocity components both along and perpendicular to the magnetic field B. Trace, giving reason, the trajectory followed by the particle. Find out the expression for the distance moved by the particle along the magnetic field in one rotation.

Discussion

38.	Five resistances are combined according to the figure. The equivalent resistance between the point X and Y will be
Answer» Five resistances are combined according to the figure. The equivalent resistance between the point X and Y will be

Discussion

39.	The coefficient of friction between the blocks of mass m and 2m is μ=2tanθ. There is no friction between the mass 2m and inclined plane. The maximum amplitude of the two block system for which there is no relative motion between both the blocks is:
Answer» The coefficient of friction between the blocks of mass $m$ and $2 m$ is $μ = 2 tan θ$ . There is no friction between the mass $2 m$ and inclined plane. The maximum amplitude of the two block system for which there is no relative motion between both the blocks is:

Discussion

40.	When a particle moves in a simple harmonic motion, its acceleration at the ends of its path is:
Answer» When a particle moves in a simple harmonic motion, its acceleration at the ends of its path is:

Discussion

41.	A sphere starts rolling down an incline of inclination θ. Find the speed of its centre when it has covered a distance l.
Answer» A sphere starts rolling down an incline of inclination $θ$ . Find the speed of its centre when it has covered a distance l.

Discussion

42.	A ball was thrown from height H and the ball hits the floor with velocity 10(^i−^j) m/s, 1.5 sec after its projection. Find initial speed of ball.
Answer» A ball was thrown from height $H$ and the ball hits the floor with velocity $10 (^i -^j) m/s,$ $1.5$ sec after its projection. Find initial speed of ball.

Discussion

43.	A person cannot see distinctly at the distance less than one metre. Calculate the power of the lens that he should use to read a book at a distance of 25 cm [CPMT 1977; MP PET 1985, 88; MP PMT 1990]
Answer» A person cannot see distinctly at the distance less than one metre. Calculate the power of the lens that he should use to read a book at a distance of 25 cm [CPMT 1977; MP PET 1985, 88; MP PMT 1990]

43.

A person cannot see distinctly at the distance less than one metre. Calculate the power of the lens that he should use to read a book at a distance of 25 cm [CPMT 1977; MP PET 1985, 88; MP PMT 1990]

Answer»

A person cannot see distinctly at the distance less than one metre. Calculate the power of the lens that he should use to read a book at a distance of 25 cm

[CPMT 1977; MP PET 1985, 88; MP PMT 1990]

Discussion

44.	A metal ball of surface area 200 cm2 and temperature 527o C is surrounded by a vessel at 27o C. If the emissivity of the metal is 0.4, then the rate of loss of heat from the ball is (ρ=5.67×10−5J/m2−s−k4)
Answer» A metal ball of surface area $200 c m^{2}$ and temperature $527^{o} C$ is surrounded by a vessel at $27^{o} C$ . If the emissivity of the metal is 0.4, then the rate of loss of heat from the ball is $(ρ = 5.67 \times 10^{- 5} J / m^{2} - s - k^{4})$

Discussion

45.	In a Callcnder's compensated constant pressure air thermometer, the volume of the bulb is 1800 cc. When the bulb is kept immersed in a vessel, 200 cc of mercury has to be poured out. Calculate the temperature of the vessel.
Answer» In a Callcnder's compensated constant pressure air thermometer, the volume of the bulb is 1800 cc. When the bulb is kept immersed in a vessel, 200 cc of mercury has to be poured out. Calculate the temperature of the vessel.

Discussion

46.	A container contains water up to a height of 20 cm and there is a point source at the centre of the bottom of the container. A rubber ring of radius r floats centrally on the water. The ceiling of the room is 2.0 m in above the water surface. (a) Find the radius of the shadow of the ring formed on the ceiling if r = 15 cm. (b) Find the maximum value of r for which the shadow of the ring is formed on the ceiling. Refractive index of water =43.
Answer» A container contains water up to a height of 20 cm and there is a point source at the centre of the bottom of the container. A rubber ring of radius r floats centrally on the water. The ceiling of the room is 2.0 m in above the water surface. (a) Find the radius of the shadow of the ring formed on the ceiling if r = 15 cm. (b) Find the maximum value of r for which the shadow of the ring is formed on the ceiling. Refractive index of water $= \frac{4}{3}$ .

46.

A container contains water up to a height of 20 cm and there is a point source at the centre of the bottom of the container. A rubber ring of radius r floats centrally on the water. The ceiling of the room is 2.0 m in above the water surface. (a) Find the radius of the shadow of the ring formed on the ceiling if r = 15 cm. (b) Find the maximum value of r for which the shadow of the ring is formed on the ceiling. Refractive index of water =43.

Answer»

A container contains water up to a height of 20 cm and there is a point source at the centre of the bottom of the container. A rubber ring of radius r floats centrally on the water. The ceiling of the room is 2.0 m in above the water surface.

(a) Find the radius of the shadow of the ring formed on the ceiling if r = 15 cm.

(b) Find the maximum value of r for which the shadow of the ring is formed on the ceiling. Refractive index of water $= \frac{4}{3}$ .

Discussion

47.	The displacement of a body from a reference point, is given by √x=2t+3 where x is in metres and t in seconds. This shows that the body is
Answer» The displacement of a body from a reference point, is given by $\sqrt{x} = 2 t + 3$ where x is in metres and t in seconds. This shows that the body is

Discussion

48.	A capacitor of capacitance C is given a charge Q. At t = 0, it is connected to an ideal battery of emf ε through a resistance R. Find the charge on the capacitor at time t.
Answer» A capacitor of capacitance C is given a charge Q. At t = 0, it is connected to an ideal battery of emf $ε$ through a resistance R. Find the charge on the capacitor at time t.

Discussion

49.	If the sound level in a room is increased from 50 dB to 60 dB, by what factor is the pressure amplitude increased ?
Answer» If the sound level in a room is increased from 50 dB to 60 dB, by what factor is the pressure amplitude increased ?

Discussion

50.	Eight dipoles with charges q and -q are placed inside a cube. The total electric flux coming out of the cube will be:
Answer» Eight dipoles with charges q and -q are placed inside a cube. The total electric flux coming out of the cube will be:

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

If the mass of the body A is m. Find the mass of the body B in terms of mass of the body A for the system to be in equilibrium.

In the system shown, mass of block A, B and C are mA=4m, mB=3m and mC=8m. If the system is released from rest, find the acceleration of block B. Assume all surfaces to be smooth and string inextensible.

A non-planar loop of conducting wire carrying a current I is placed as shown in the figure. Each of the straight sections of the loop is of length 2a. The magnetic field due to this loop at the point P (a, 0, a) points in the direction

In Young’s double slit experiment, the slits are horizontal. The intensity at a point P as shown in figure is 34I0, where I0 is the maximum intensity. Then the value of θ is

The force F required to extend a rubber wire by a length x from its natural length was found to vary as in diagram. The energy stored in the rubber for an extension of 5 m is

A layer of benzene floats on water. If the angle of incidence of the light entering benzene from air is 60∘, then the angle that light makes with normal in water is (Refractive index of water =43)

Sound of wavelength λ passes through a Quincke’s tube, which is adjusted to give a maximum intensity I0. Through what distance should the sliding tube be moved to give an intensity I02?

A gun is mounted on a plateau 960 m away from it’s edge as shown. Height of plateau is 960 m. The gun can fire shells with a velocity of 100 m/s at any angle. Of the following choices, what is the minimum distance (OP)x from the edge of plateau where the shell of gun can reach?

A continuous flow water heater (geyser) has an electrical power rating =2 kW and efficiency of conversion of electrical power into heat =80%. If water is flowing through the device at the rate of 100 cc/sec, and the inlet temperature is 10∘C, the outlet temperature will be

When forces F1,F2,F3 are acting on a particle of mass m such that F2 and F3 are mutually perpendicular, then the particle remains stationary. If the force F1 is now removed then the magnitude of acceleration of the particle is

The elevator shown in figure is descending with an acceleration of 2m/s2. The mass of the block A is 0.5 kg. What force is exerted by the block a on the block B ?

An image 23 the size of the object is formed by a convex lens at a distance of 12 cm from it. Find the focal length of the lens.

An infinite line charge produces an electric field of 9×104 NC−1 at a distance of 2 cm. Calculate the linear charge density.

Three blocks of masses m1, m2 and m3 are connected by massless strings as shown in the figure and placed on a frictionless table. A force of 40 N pulls the system. Then calculate the value of T (in N) if m1=10 kg,m2=6 kg and m3=4 kg.

A particle moves with deceleration along the circle of radius R so that at any moment of time its tangential and centripetal accelerations are equal in moduli. At the initial moment t=0, the speed of the particle equals v0. Then The total acceleration of the particle is

When 100 V dc is applied across a coil, a current of one ampere flows through it, but when 100 V ac of 50 Hz is applied to the same coil, only 0.5 amp flows. Calculate the resistance and inductance of the coil.

A parallelogram has diagonals expressed as →A=5^i−4^j+3^k and →B=3^i+2^j−^k. Area of parallelogram is

Two smooth cylindrical bars weighing W each, lie next to each other in contact. A similar third bar is placed over the two bars as shown in figure. Neglecting friction, the minimum horizontal force on each lower bar necessary to keep them together is

What are the physical quantities on which vectors and scalers are differentiated?

Show that the vectors 2^i−3^j+4^k and −4^i+6^j−8^k are collinear.

A train starts from rest and its speed increases at a constant rate α to v and then remains constant for an interval and finally decreases to zero at a constant rate β. The total distance travelled by train is l. The time taken to complete the journey is t. Then,

What is the relative velocity when two bodies move in opposite direction?

Find the approximate change in the volume V of a cube of side x metre caused by increasing the side by 1%.

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 origin varies as?

Why does magnetic field increases the resistivity of all metals except iron , cobalt and nickel ?

An ideal monoatomic gas is taken round the cycle ABCA as shown in the Fig. 17.9 The work done during the cycle is

A body is dropped from a certain height h (h is very large) and second body is thrown downward from the same height h with velocity of 5 m/s simultaneously. What will be difference in heights of the two bodies after 3s ?

Q. A lamp is connected in series with a capacitor . Predict your observations when the system is connected first across a DC and then an AC source . What happens if the capacitance of the capacitor is reduced ?

Which of the following doesn't use the application of Conservation of Angular Momentum?

Five resistances are combined according to the figure. The equivalent resistance between the point X and Y will be

The coefficient of friction between the blocks of mass m and 2m is μ=2tanθ. There is no friction between the mass 2m and inclined plane. The maximum amplitude of the two block system for which there is no relative motion between both the blocks is:

When a particle moves in a simple harmonic motion, its acceleration at the ends of its path is:

A sphere starts rolling down an incline of inclination θ. Find the speed of its centre when it has covered a distance l.

A ball was thrown from height H and the ball hits the floor with velocity 10(^i−^j) m/s, 1.5 sec after its projection. Find initial speed of ball.

A person cannot see distinctly at the distance less than one metre. Calculate the power of the lens that he should use to read a book at a distance of 25 cm [CPMT 1977; MP PET 1985, 88; MP PMT 1990]

A metal ball of surface area 200 cm2 and temperature 527o C is surrounded by a vessel at 27o C. If the emissivity of the metal is 0.4, then the rate of loss of heat from the ball is (ρ=5.67×10−5J/m2−s−k4)

In a Callcnder's compensated constant pressure air thermometer, the volume of the bulb is 1800 cc. When the bulb is kept immersed in a vessel, 200 cc of mercury has to be poured out. Calculate the temperature of the vessel.

The displacement of a body from a reference point, is given by √x=2t+3 where x is in metres and t in seconds. This shows that the body is

A capacitor of capacitance C is given a charge Q. At t = 0, it is connected to an ideal battery of emf ε through a resistance R. Find the charge on the capacitor at time t.

If the sound level in a room is increased from 50 dB to 60 dB, by what factor is the pressure amplitude increased ?

Eight dipoles with charges q and -q are placed inside a cube. The total electric flux coming out of the cube will be: