50278 + Interview Questions in Physics

1.	(a) Define electric flux. Is it a scalar or a vector quantity ? A point charge q is at a distance of d/2 directly above the centre of a square of side d, as shown in the figure. Use Gauss' law to obtain the expression for the electric flux through the square. (b) If the point charge is now moved to a distance 'd' from the centre of the square and the side of the square is doubled, explain how the electric flux will be affected.
Answer» (a) Define electric flux. Is it a scalar or a vector quantity ? A point charge q is at a distance of d/2 directly above the centre of a square of side d, as shown in the figure. Use Gauss' law to obtain the expression for the electric flux through the square. (b) If the point charge is now moved to a distance 'd' from the centre of the square and the side of the square is doubled, explain how the electric flux will be affected.

Discussion

2.	The mass of a body measured by a physical balance in a lift at rest is found to be m. If the lift is going up with an acceleration a, its mass will be measured as
Answer» The mass of a body measured by a physical balance in a lift at rest is found to be m. If the lift is going up with an acceleration a, its mass will be measured as

2.

The mass of a body measured by a physical balance in a lift at rest is found to be m. If the lift is going up with an acceleration a, its mass will be measured as

Answer»

The mass of a body measured by a physical balance in a lift at rest is found to be m. If the lift is going up with an acceleration a, its mass will be measured as

Discussion

3.	A wave pulse is travelling on a string with a speed v towards the positive X-axis. The shape of the string at t = 0 is given by g(x) =A sin(xa) where A and a are constants. Write the equation of the wave for a general time t, if the wave speed is v.
Answer» A wave pulse is travelling on a string with a speed v towards the positive X-axis. The shape of the string at t = 0 is given by g(x) = $A s i n (\frac{x}{a})$ where A and a are constants. Write the equation of the wave for a general time t, if the wave speed is v.

Discussion

4.	Two blocks are connected over a massless pulley as shown in the figure. The mass of block A is 10 kg and coefficient of kinetic friction is 0.2. Block A slides down the incline at constant speed. The mass of the block B (in kg) is
Answer» Two blocks are connected over a massless pulley as shown in the figure. The mass of block $A$ is $10 kg$ and coefficient of kinetic friction is $0.2$ . Block $A$ slides down the incline at constant speed. The mass of the block $B$ (in $kg$ ) is

Discussion

5.	The power of a thin convex lens (aμg=1.5) is +5.0 D. When it is placed in a liquid of refractive index aμl,then it behaves as a concave lens of local length 100 cm. The refractive index of the liquid aμl will be
Answer» The power of a thin convex lens $(_{a} μ_{g} = 1.5)$ is +5.0 D. When it is placed in a liquid of refractive index $_{a} μ_{l}$ ,then it behaves as a concave lens of local length 100 cm. The refractive index of the liquid $_{a} μ_{l}$ will be

Discussion

6.	If A=⎡⎢⎢⎢⎣0−tanθ2tanθ20⎤⎥⎥⎥⎦ and (I2+A)(I2−A)−1=[a−bba] , then 13(a2+b2) is equal to
Answer» If $A = ⎡ ⎢⎢⎢ ⎣ \begin{matrix} 0 & - tan \frac{θ}{2} tan \frac{θ}{2} & 0 \end{matrix} ⎤ ⎥⎥⎥ ⎦$ and $(I_{2} + A) (I_{2} - A)^{- 1} = [\begin{matrix} a & - b b & a \end{matrix}]$ , then $13 (a^{2} + b^{2})$ is equal to

Discussion

7.	Light of wavelength strikes a photo-sensitive surface and electrons are ejected with kinetic energy E. If the kinetic energy is to be increased to 2E, the wavelength must be changed to
Answer» Light of wavelength strikes a photo-sensitive surface and electrons are ejected with kinetic energy E. If the kinetic energy is to be increased to 2E, the wavelength must be changed to

Discussion

8.	In a given circuit, if peak voltage across resistance is 8V, then the value of capacitance is
Answer» In a given circuit, if peak voltage across resistance is 8V, then the value of capacitance is

Discussion

9.	A body of mass m is suspended by two strings making angles α and β with the horizontal (as shown in the figure). Find the tensions in the strings?
Answer» A body of mass m is suspended by two strings making angles $α$ and $β$ with the horizontal (as shown in the figure). Find the tensions in the strings?

9.

A body of mass m is suspended by two strings making angles α and β with the horizontal (as shown in the figure). Find the tensions in the strings?

Answer»

A body of mass m is suspended by two strings making angles $α$ and $β$ with the horizontal (as shown in the figure). Find the tensions in the strings?

Discussion

10.	Find the angular velocity of a body rotating with an acceleration of 2 rev/s2 as it completes the 5th revolution after the start.
Answer» Find the angular velocity of a body rotating with an acceleration of 2 rev/s $^{2}$ as it completes the 5th revolution after the start.

Discussion

11.	Rasheed got a playing top (lattu) as his birthday present, which surprisingly had no colour on it. He wanted to colour it with his crayons. The top is shaped like a cone surmounted by a hemisphere (see Fig). The entire top is 5 cm in height and the diameter of the top is 3.5 cm. Find the area he has to colour. (Take π=227) [4 MARKS]
Answer» Rasheed got a playing top (lattu) as his birthday present, which surprisingly had no colour on it. He wanted to colour it with his crayons. The top is shaped like a cone surmounted by a hemisphere (see Fig). The entire top is 5 cm in height and the diameter of the top is 3.5 cm. Find the area he has to colour. (Take $π = \frac{22}{7}$ ) [4 MARKS]

11.

Rasheed got a playing top (lattu) as his birthday present, which surprisingly had no colour on it. He wanted to colour it with his crayons. The top is shaped like a cone surmounted by a hemisphere (see Fig). The entire top is 5 cm in height and the diameter of the top is 3.5 cm. Find the area he has to colour. (Take π=227) [4 MARKS]

Answer»

Rasheed got a playing top (lattu) as his birthday present, which surprisingly had no colour on it. He wanted to colour it with his crayons. The top is shaped like a cone surmounted by a hemisphere (see Fig). The entire top is 5 cm in height and the diameter of the top is 3.5 cm. Find the area he has to colour. (Take $π = \frac{22}{7}$ ) [4 MARKS]

Discussion

12.	A block of mass m is attached with a spring of force constant k. The block is kept on a frictionless plank. The other end of the spring is connected with the plank. Mass of the plank is M and it is also kept on a frictionless surface. Initially, the system is stationary. A sharp impulse P is applied on the block as shown. The maximum compression in the spring will be
Answer» A block of mass m is attached with a spring of force constant k. The block is kept on a frictionless plank. The other end of the spring is connected with the plank. Mass of the plank is M and it is also kept on a frictionless surface. Initially, the system is stationary. A sharp impulse P is applied on the block as shown. The maximum compression in the spring will be

12.

A block of mass m is attached with a spring of force constant k. The block is kept on a frictionless plank. The other end of the spring is connected with the plank. Mass of the plank is M and it is also kept on a frictionless surface. Initially, the system is stationary. A sharp impulse P is applied on the block as shown. The maximum compression in the spring will be

Answer»

A block of mass m is attached with a spring of force constant k. The block is kept on a frictionless plank. The other end of the spring is connected with the plank. Mass of the plank is M and it is also kept on a frictionless surface.

Initially, the system is stationary. A sharp impulse P is applied on the block as shown. The maximum compression in the spring will be

Discussion

13.	Please explain why mgh/ 1+h/R is the change in potential energy when a body is raised to height h from earth's surface
Answer» Please explain why mgh/ 1+h/R is the change in potential energy when a body is raised to height h from earth's surface

Discussion

14.	Find out torque about points A, O and B if →F = 10^i
Answer» Find out torque about points $A$ , $O$ and $B$ if $\to F$ = $10^i$

14.

Find out torque about points A, O and B if →F = 10^i

Answer»

Find out torque about points $A$ , $O$ and $B$ if $\to F$ = $10^i$

Discussion

15.	A solid sphere A of mass m rolls without slipping on an inclined plane of inclination 30∘. Coefficient of friction of the inclined plane is μ. Then, which of the following options is satisfied when the sphere undergoes pure rolling motion?
Answer» A solid sphere $A$ of mass $m$ rolls without slipping on an inclined plane of inclination $30^{\circ}$ . Coefficient of friction of the inclined plane is $μ$ . Then, which of the following options is satisfied when the sphere undergoes pure rolling motion?

Discussion

16.	A spherical drop of water has 1 mm radius. If the surface tension of water is 75×10−3 N/m, then the difference in pressure between the inside and outside of the drop is
Answer» A spherical drop of water has $1 mm$ radius. If the surface tension of water is $75 \times 10^{- 3} N/m$ , then the difference in pressure between the inside and outside of the drop is

Discussion

17.	All the particles of a body are situated at a distance R from the origin. The distance of the centre of mass of the body from the origin is
Answer» All the particles of a body are situated at a distance $R$ from the origin. The distance of the centre of mass of the body from the origin is

Discussion

18.	A steel ball strikes a steel plate at an angle θ with the vertical. If the coefficient of restitution is e, the angle at which the rebound will take place is
Answer» A steel ball strikes a steel plate at an angle $θ$ with the vertical. If the coefficient of restitution is $e$ , the angle at which the rebound will take place is

Discussion

19.	An inductance of 2.0 H, a capacitance of 18μF and a resistance of 10kΩ are connected to an AC source of 20 V with adjustable frequency. (a) What frequency should be chosen to maximise the current in the circuit? (b) What is the value of this maximum current ?
Answer» An inductance of 2.0 H, a capacitance of $18 μ F$ and a resistance of 10 $k Ω$ are connected to an AC source of 20 V with adjustable frequency. (a) What frequency should be chosen to maximise the current in the circuit? (b) What is the value of this maximum current ?

Discussion

20.	Does the nature of EM wave depend on the magnitude of acceleration of the charged particle?
Answer» Does the nature of EM wave depend on the magnitude of acceleration of the charged particle?

Discussion

21.	The length of a metal wire is l1 when the tension in it is T1 and is l2 when the tension is T2. The natural length of the wire is
Answer» The length of a metal wire is $l_{1}$ when the tension in it is $T_{1}$ and is $l_{2}$ when the tension is $T_{2}$ . The natural length of the wire is

Discussion

22.	A swimmer crosses a river with minimum possible time 10 second. And, when he reaches the other end starts swimming in the direction from where he started swimming. Keeping the direction fixed the swimmer crosses the river in 15 sec. the ratio of speed of swimmer with respect to water and the speed of river flow is (Assume constant speed of river & swimmer)
Answer» A swimmer crosses a river with minimum possible time $10$ second. And, when he reaches the other end starts swimming in the direction from where he started swimming. Keeping the direction fixed the swimmer crosses the river in $15$ sec. the ratio of speed of swimmer with respect to water and the speed of river flow is (Assume constant speed of river & swimmer)

Discussion

23.	A 100g iron ball having velocity 10m/s collides with a wall at an angle 30° and rebounds with the same angle .If the period of contact between the ball and the wall is 0.1 second ,then find the force experienced by the wall.
Answer» A 100g iron ball having velocity 10m/s collides with a wall at an angle 30° and rebounds with the same angle .If the period of contact between the ball and the wall is 0.1 second ,then find the force experienced by the wall.

Discussion

24.	A pump motor is used to deliver water at a certain rate from a given pipe. To obtain twice as much water from the same pipe in same time, Power of the motor has to be increased to?
Answer» A pump motor is used to deliver water at a certain rate from a given pipe. To obtain twice as much water from the same pipe in same time, Power of the motor has to be increased to?

Discussion

25.	What happens to range of ammeter if the value of shunt connected decreases?
Answer» What happens to range of ammeter if the value of shunt connected decreases?

Discussion

26.	A meter stick is pivoted about its centre. A piece of wax of mass 20 g travelling horizontally and perpendicular to it at 5 m/s strikes and adheres to one end of the stick which starts to rotate in a horizontal circle. Given, the moment of inertia of the stick and wax about the pivot is 0.02 kg m2, the angular velocity of the stick is
Answer» A meter stick is pivoted about its centre. A piece of wax of mass $20 g$ travelling horizontally and perpendicular to it at $5 m/s$ strikes and adheres to one end of the stick which starts to rotate in a horizontal circle. Given, the moment of inertia of the stick and wax about the pivot is $0.02 {kg m}^{2}$ , the angular velocity of the stick is

Discussion

27.	In our byju's classes Anand sir says that you should reset the time to when we know the the motion of the object I have one doubt on that why I need to reset my watch
Answer» In our byju's classes Anand sir says that you should reset the time to when we know the the motion of the object I have one doubt on that why I need to reset my watch

Discussion

28.	A boy standing on a stationary lift (open from above) throws a ball upwards with maximum initial speed he can, equal to 49 m/s. How much time does ball take to return to his hands? If lift starts moving up with a uniform speed of 5 m/s and the boy again throws the ball up with the maximum speed he can, how long does the ball take to return to his hands?
Answer» A boy standing on a stationary lift (open from above) throws a ball upwards with maximum initial speed he can, equal to 49 m/s. How much time does ball take to return to his hands? If lift starts moving up with a uniform speed of 5 m/s and the boy again throws the ball up with the maximum speed he can, how long does the ball take to return to his hands?

Discussion

29.	The magnifying power of a telescope is 9. When it is adjusted for parallel rays, the distance between the objective and eyepiece is found to be 20 cm. The focal lengths of lenses are:
Answer» The magnifying power of a telescope is 9. When it is adjusted for parallel rays, the distance between the objective and eyepiece is found to be 20 cm. The focal lengths of lenses are:

Discussion

30.	Mass density and radius of a solid sphere are ρ, R respectively. Gravitational field at an internal point which is at a distance r from the centre is.
Answer» Mass density and radius of a solid sphere are ρ, R respectively. Gravitational field at an internal point which is at a distance r from the centre is.

Discussion

31.	What is recoil velocity of a gun? How can you derive the expression for recoil velocity of gun?
Answer» What is recoil velocity of a gun? How can you derive the expression for recoil velocity of gun?

Discussion

32.	Two blocks are in contact on a frictionless table masses 2m and m respectively as shown in figure. Force F is applied on mass 2m then system moves towards right. Now the same force F is applied on m. The ratio of force of contact between the two blocks will be in the two cases respectively.
Answer» Two blocks are in contact on a frictionless table masses $2 m$ and $m$ respectively as shown in figure. Force F is applied on mass $2 m$ then system moves towards right. Now the same force F is applied on $m$ . The ratio of force of contact between the two blocks will be in the two cases respectively.

32.

Two blocks are in contact on a frictionless table masses 2m and m respectively as shown in figure. Force F is applied on mass 2m then system moves towards right. Now the same force F is applied on m. The ratio of force of contact between the two blocks will be in the two cases respectively.

Answer»

Two blocks are in contact on a frictionless table masses $2 m$ and $m$ respectively as shown in figure. Force F is applied on mass $2 m$ then system moves towards right. Now the same force F is applied on $m$ . The ratio of force of contact between the two blocks will be in the two cases respectively.

Discussion

33.	A bar magnet of magnetic moment 6J/T is aligned at 60 degrees with a uniform external magnetic field of 0.44T . Calculate (a) the work done in turning the magnet to align its magnetic moment (i)Normal to the magnetic field (ii) opposite to the magnetic field and (b) the torque on the magnet in the final orientation in case (ii)
Answer» A bar magnet of magnetic moment 6J/T is aligned at 60 degrees with a uniform external magnetic field of 0.44T . Calculate (a) the work done in turning the magnet to align its magnetic moment (i)Normal to the magnetic field (ii) opposite to the magnetic field and (b) the torque on the magnet in the final orientation in case (ii)

Discussion

34.	A current I flows along infinitely long straight thin counductor , then magnetic field induction at any point on the counductor is
Answer» A current I flows along infinitely long straight thin counductor , then magnetic field induction at any point on the counductor is

Discussion

35.	A bar magnet is dropped vertically downward through a wire loop held horizontal ly .the magnet will fall with non uniform acceleration less than g.why?
Answer» A bar magnet is dropped vertically downward through a wire loop held horizontal ly .the magnet will fall with non uniform acceleration less than g.why?

Discussion

36.	A satellite moves in a circle around the earth. The radius of this circle is equal to one half the radius of the moon's orbit. This satellite completes one revolution in
Answer» A satellite moves in a circle around the earth. The radius of this circle is equal to one half the radius of the moon's orbit. This satellite completes one revolution in

Discussion

37.	The MOI of a uniform circular disc is maximum about an axis perpendicular to the disc and passing through point
Answer» The MOI of a uniform circular disc is maximum about an axis perpendicular to the disc and passing through point

Discussion

38.	Sodium chloride crystal has FCC structure. Its density is 2.163 x 103 kg m-3. What will be the edge length of the unit cell cube?
Answer» Sodium chloride crystal has FCC structure. Its density is 2.163 x 10³ kg m^-3. What will be the edge length of the unit cell cube?

Discussion

39.	A projectile thrown at an angle of 30∘ with the horizontal has a range R1. Another projectile thrown, with the same velocity, at an angle 30∘ with the vertical, has a range R2. The relation between R1 and R2 is
Answer» A projectile thrown at an angle of $30^{\circ}$ with the horizontal has a range $R_{1}$ . Another projectile thrown, with the same velocity, at an angle $30^{\circ}$ with the vertical, has a range $R_{2}$ . The relation between $R_{1}$ and $R_{2}$ is

Discussion

40.	When a conductor is placed in an external electric field, the acceleration of its electrons will be
Answer» When a conductor is placed in an external electric field, the acceleration of its electrons will be

Discussion

41.	An external torque will always cause a change in
Answer» An external torque will always cause a change in

Discussion

42.	If only the conservative forces are acting on the body, then its total
Answer» If only the conservative forces are acting on the body, then its total

Discussion

43.	A light is at the top of a tower of height 47 meter. A man of height 2 meter, who is 90 meter away horizontally from the foot of the tower starts running with velocity 15m/sec towards the foot of the tower. At the same instant a ball which is placed in the same vertical plane of tower and man, dropped from the same height of the tower, 5meter horizontally away from the light on the side of the tower where man is placed. Assuming that ball falls according to the law S=5t2 Answer the following The rate (in m/sec) at which the length of mans shadow decreases at the instant t = 2 seconds, is
Answer» A light is at the top of a tower of height 47 meter. A man of height 2 meter, who is 90 meter away horizontally from the foot of the tower starts running with velocity 15m/sec towards the foot of the tower. At the same instant a ball which is placed in the same vertical plane of tower and man, dropped from the same height of the tower, 5meter horizontally away from the light on the side of the tower where man is placed. Assuming that ball falls according to the law $S = 5 t^{2}$ Answer the following The rate (in m/sec) at which the length of mans shadow decreases at the instant t = 2 seconds, is

Discussion

44.	A silk cloth rubbed with a glass rod acquire a charge (-1.6 - 10 -19) C. Then the charge on the glass rod is
Answer» A silk cloth rubbed with a glass rod acquire a charge (-1.6 - 10 ^-19) C. Then the charge on the glass rod is

Discussion

45.	(a) What is the largest average velocity of blood flow in an artery of radius 2×10–3 m if the flow must remain laminar? (b) What is the corresponding flow rate? (Take viscosity of blood to be 2.084×10–3 Pa s).
Answer» (a) What is the largest average velocity of blood flow in an artery of radius $2 \times 10^{- 3}$ m if the flow must remain laminar? (b) What is the corresponding flow rate? (Take viscosity of blood to be $2.084 \times 10^{- 3}$ Pa s).

Discussion

46.	The lower surface of the cube floating in water just touches the free end of a vertical spring fixed at the bottom of the vessel. The maximum weight that can be put on the block without wetting it is-
Answer» The lower surface of the cube floating in water just touches the free end of a vertical spring fixed at the bottom of the vessel. The maximum weight that can be put on the block without wetting it is-

Discussion

47.	A stone A is dropped from rest from height h above ground. A second stone B is simultaneously thrown vertically up with velocity v. Find v so that B meets midway between their initial positions.
Answer» A stone $A$ is dropped from rest from height $h$ above ground. A second stone $B$ is simultaneously thrown vertically up with velocity $v$ . Find $v$ so that $B$ meets midway between their initial positions.

Discussion

48.	A 150 m long train is moving with a uniform velocity of 45 km/h. The time taken by the train to cross a bridge of length 850 meters is
Answer» A 150 m long train is moving with a uniform velocity of 45 km/h. The time taken by the train to cross a bridge of length 850 meters is

Discussion

49.	If ABCD is a cyclic quadrilateral inscribed in a circle of radius 2 units such that AB=1, BD=2√3 then AD=
Answer» If $A B C D$ is a cyclic quadrilateral inscribed in a circle of radius 2 units such that $A B = 1, B D = 2 \sqrt{3}$ then $A D =$

49.

If ABCD is a cyclic quadrilateral inscribed in a circle of radius 2 units such that AB=1, BD=2√3 then AD=

Answer»

If $A B C D$ is a cyclic quadrilateral inscribed in a circle of radius 2 units such that $A B = 1, B D = 2 \sqrt{3}$ then $A D =$

Discussion

50.	A force F=(5^i+3^j) newton is applied over a particle which displaces it from its origin to the point r=(2^i−1^j) metre. The work done on the particle is
Answer» A force $F = (5^i + 3^j)$ newton is applied over a particle which displaces it from its origin to the point $r = (2^i - 1^j)$ metre. The work done on the particle is

50.

A force F=(5^i+3^j) newton is applied over a particle which displaces it from its origin to the point r=(2^i−1^j) metre. The work done on the particle is

Answer»

A force $F = (5^i + 3^j)$ newton is applied over a particle which displaces it from its origin to the point $r = (2^i - 1^j)$ metre. The work done on the particle is

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

The mass of a body measured by a physical balance in a lift at rest is found to be m. If the lift is going up with an acceleration a, its mass will be measured as

A wave pulse is travelling on a string with a speed v towards the positive X-axis. The shape of the string at t = 0 is given by g(x) =A sin(xa) where A and a are constants. Write the equation of the wave for a general time t, if the wave speed is v.

Two blocks are connected over a massless pulley as shown in the figure. The mass of block A is 10 kg and coefficient of kinetic friction is 0.2. Block A slides down the incline at constant speed. The mass of the block B (in kg) is

The power of a thin convex lens (aμg=1.5) is +5.0 D. When it is placed in a liquid of refractive index aμl,then it behaves as a concave lens of local length 100 cm. The refractive index of the liquid aμl will be

If A=⎡⎢⎢⎢⎣0−tanθ2tanθ20⎤⎥⎥⎥⎦ and (I2+A)(I2−A)−1=[a−bba] , then 13(a2+b2) is equal to

Light of wavelength strikes a photo-sensitive surface and electrons are ejected with kinetic energy E. If the kinetic energy is to be increased to 2E, the wavelength must be changed to

In a given circuit, if peak voltage across resistance is 8V, then the value of capacitance is

A body of mass m is suspended by two strings making angles α and β with the horizontal (as shown in the figure). Find the tensions in the strings?

Find the angular velocity of a body rotating with an acceleration of 2 rev/s2 as it completes the 5th revolution after the start.

Please explain why mgh/ 1+h/R is the change in potential energy when a body is raised to height h from earth's surface

Find out torque about points A, O and B if →F = 10^i

A solid sphere A of mass m rolls without slipping on an inclined plane of inclination 30∘. Coefficient of friction of the inclined plane is μ. Then, which of the following options is satisfied when the sphere undergoes pure rolling motion?

A spherical drop of water has 1 mm radius. If the surface tension of water is 75×10−3 N/m, then the difference in pressure between the inside and outside of the drop is

All the particles of a body are situated at a distance R from the origin. The distance of the centre of mass of the body from the origin is

A steel ball strikes a steel plate at an angle θ with the vertical. If the coefficient of restitution is e, the angle at which the rebound will take place is

An inductance of 2.0 H, a capacitance of 18μF and a resistance of 10kΩ are connected to an AC source of 20 V with adjustable frequency. (a) What frequency should be chosen to maximise the current in the circuit? (b) What is the value of this maximum current ?

Does the nature of EM wave depend on the magnitude of acceleration of the charged particle?

The length of a metal wire is l1 when the tension in it is T1 and is l2 when the tension is T2. The natural length of the wire is

A 100g iron ball having velocity 10m/s collides with a wall at an angle 30° and rebounds with the same angle .If the period of contact between the ball and the wall is 0.1 second ,then find the force experienced by the wall.

A pump motor is used to deliver water at a certain rate from a given pipe. To obtain twice as much water from the same pipe in same time, Power of the motor has to be increased to?

What happens to range of ammeter if the value of shunt connected decreases?

In our byju's classes Anand sir says that you should reset the time to when we know the the motion of the object I have one doubt on that why I need to reset my watch

The magnifying power of a telescope is 9. When it is adjusted for parallel rays, the distance between the objective and eyepiece is found to be 20 cm. The focal lengths of lenses are:

Mass density and radius of a solid sphere are ρ, R respectively. Gravitational field at an internal point which is at a distance r from the centre is.

What is recoil velocity of a gun? How can you derive the expression for recoil velocity of gun?

Two blocks are in contact on a frictionless table masses 2m and m respectively as shown in figure. Force F is applied on mass 2m then system moves towards right. Now the same force F is applied on m. The ratio of force of contact between the two blocks will be in the two cases respectively.

A current I flows along infinitely long straight thin counductor , then magnetic field induction at any point on the counductor is

A bar magnet is dropped vertically downward through a wire loop held horizontal ly .the magnet will fall with non uniform acceleration less than g.why?

A satellite moves in a circle around the earth. The radius of this circle is equal to one half the radius of the moon's orbit. This satellite completes one revolution in

The MOI of a uniform circular disc is maximum about an axis perpendicular to the disc and passing through point

Sodium chloride crystal has FCC structure. Its density is 2.163 x 103 kg m-3. What will be the edge length of the unit cell cube?

A projectile thrown at an angle of 30∘ with the horizontal has a range R1. Another projectile thrown, with the same velocity, at an angle 30∘ with the vertical, has a range R2. The relation between R1 and R2 is

When a conductor is placed in an external electric field, the acceleration of its electrons will be

An external torque will always cause a change in

If only the conservative forces are acting on the body, then its total

A silk cloth rubbed with a glass rod acquire a charge (-1.6 - 10 -19) C. Then the charge on the glass rod is

(a) What is the largest average velocity of blood flow in an artery of radius 2×10–3 m if the flow must remain laminar? (b) What is the corresponding flow rate? (Take viscosity of blood to be 2.084×10–3 Pa s).

The lower surface of the cube floating in water just touches the free end of a vertical spring fixed at the bottom of the vessel. The maximum weight that can be put on the block without wetting it is-

A stone A is dropped from rest from height h above ground. A second stone B is simultaneously thrown vertically up with velocity v. Find v so that B meets midway between their initial positions.

A 150 m long train is moving with a uniform velocity of 45 km/h. The time taken by the train to cross a bridge of length 850 meters is

If ABCD is a cyclic quadrilateral inscribed in a circle of radius 2 units such that AB=1, BD=2√3 then AD=

A force F=(5^i+3^j) newton is applied over a particle which displaces it from its origin to the point r=(2^i−1^j) metre. The work done on the particle is