50278 + Interview Questions in Physics Page 269 InterviewSolution

13401.	Consider the situation shown in figure (6-E2). Calculate (a) the acceleration of the 1.0 kg blocks, (b) the tension inthe string ocnecting the 1.0 kg blocks and (c) the tensionin th tring attached to 0.50 kg.
Answer» Consider the situation shown in figure (6-E2). Calculate (a) the acceleration of the 1.0 kg blocks, (b) the tension inthe string ocnecting the 1.0 kg blocks and (c) the tensionin th tring attached to 0.50 kg.

13401.

Consider the situation shown in figure (6-E2). Calculate (a) the acceleration of the 1.0 kg blocks, (b) the tension inthe string ocnecting the 1.0 kg blocks and (c) the tensionin th tring attached to 0.50 kg.

Answer»

Consider the situation shown in figure (6-E2). Calculate (a) the acceleration of the 1.0 kg blocks, (b) the tension inthe string ocnecting the 1.0 kg blocks and (c) the tensionin th tring attached to 0.50 kg.

Discussion

13402.	The average rotational kinetic energy for the diatomic gas molecules is (kB is Boltzmann constant and T is absolute temperature)
Answer» The average rotational kinetic energy for the diatomic gas molecules is $(k_{B}$ is Boltzmann constant and $T$ is absolute temperature)

Discussion

13403.	A bolt of mass 0.3 kg falls from the ceiling of an elevator moving down with an uniform speed of 7 m s¯¹. It hits the floor of the elevator (length of the elevator = 3 m) and does not rebound. What is the heat produced by the impact ? Would your answer be different if the elevator were stationary ?
Answer» A bolt of mass 0.3 kg falls from the ceiling of an elevator moving down with an uniform speed of 7 m s¯¹. It hits the floor of the elevator (length of the elevator = 3 m) and does not rebound. What is the heat produced by the impact ? Would your answer be different if the elevator were stationary ?

Discussion

13404.	Derive an expression for electric field due to uniformly charged infinite plane sheet ?
Answer» Derive an expression for electric field due to uniformly charged infinite plane sheet ?

Discussion

13405.	How is an ammeter connected in a circuit?
Answer» How is an ammeter connected in a circuit?

Discussion

13406.	99. A body of mass 5 kg is suspended by a spring balance on an inclined plane as shown in figure. The spring balance measure
Answer» 99. A body of mass 5 kg is suspended by a spring balance on an inclined plane as shown in figure. The spring balance measure

Discussion

13407.	A ball with initial velocity 1 m/s strikes a stationary ball of the same mass. If the final total kinetic energy is 50% greater than the original kinetic energy, the magnitude of the relative velocity between the two balls after collision (assuming collinear collision), is
Answer» A ball with initial velocity $1 m/s$ strikes a stationary ball of the same mass. If the final total kinetic energy is $50 %$ greater than the original kinetic energy, the magnitude of the relative velocity between the two balls after collision (assuming collinear collision), is

Discussion

13408.	Two conducting large plates P1 and P2 are placed near to each other at very small separation 'd'. The plate area of either face of plate is A. Now a charge +2Q is given to plate P1 and –Q to the plate P2 (neglect ends effects). Potential difference between the plates P1 and P2
Answer» Two conducting large plates $P_{1}$ and $P_{2}$ are placed near to each other at very small separation 'd'. The plate area of either face of plate is A. Now a charge $+ 2 Q$ is given to plate $P_{1}$ and $- Q$ to the plate $P_{2}$ (neglect ends effects). Potential difference between the plates $P_{1}$ and $P_{2}$

Discussion

13409.	A wave moves with speed 300 m/s on a wire which is under a tension of 500 N. Find how much the tension must be changed to increase the speed to 312 m/s?
Answer» A wave moves with speed 300 m/s on a wire which is under a tension of 500 N. Find how much the tension must be changed to increase the speed to 312 m/s?

Discussion

13410.	why chandrayan2 mission launched from south give reason with the help of gravitation force concep
Answer» why chandrayan2 mission launched from south give reason with the help of gravitation force concep

Discussion

13411.	A parallel plate capacitor with air between the plates has a capacitance of 8 pF (1pF = 10–12 F). What will be the capacitance if the distance between the plates is reduced by half, and the space between them is filled with a substance of dielectric constant 6?
Answer» A parallel plate capacitor with air between the plates has a capacitance of 8 pF (1pF = 10–12 F). What will be the capacitance if the distance between the plates is reduced by half, and the space between them is filled with a substance of dielectric constant 6?

Discussion

13412.	A force of 5 N acts on a particle along a direction making an angle of60∘ with vertical. Its vertical component be
Answer» A force of 5 N acts on a particle along a direction making an angle of $60^{\circ}$ with vertical. Its vertical component be

Discussion

13413.	50.Two concentric hollow spheres of radius r&R are shown. The charge on outer shell is Q. What charge should be given to the inner sphere so that the potential at any point outside the sphere is zero?
Answer» 50.Two concentric hollow spheres of radius r&R are shown. The charge on outer shell is Q. What charge should be given to the inner sphere so that the potential at any point outside the sphere is zero?

Discussion

13414.	An ideal monoatomic gas is taken around the cycle ABCD as shown in figure below. Work done during the cycle is
Answer» An ideal monoatomic gas is taken around the cycle $A B C D$ as shown in figure below. Work done during the cycle is

Discussion

13415.	Laws of motion
Answer» Laws of motion

Discussion

13416.	Points A and B are situated along the extended axis of 2 cm long bar magnet at a distance x and 2x cm respectively. From the pole nearer to the points, the ratio of the magnetic field at A and B will be
Answer» Points A and B are situated along the extended axis of 2 cm long bar magnet at a distance x and 2x cm respectively. From the pole nearer to the points, the ratio of the magnetic field at A and B will be

Discussion

13417.	A system consists of a disc and square with equal surface mass density as shown in figure. The centre of mass is at the point of contact.The relation between L and R is L=(2π)nR.Then, find n. (Answer up to two decimal places)
Answer» A system consists of a disc and square with equal surface mass density as shown in figure. The centre of mass is at the point of contact.The relation between $L$ and $R$ is $L = (2 π)^{n} R$ .Then, find $n$ . (Answer up to two decimal places)

Discussion

13418.	The frequency of oscillation of a bar magnet in an oscillation magnetometer in the earth's magnetic field is 40 oscillations per minute. A short bar magnet is placed to the north of the magnetometer, at a separation of 20 cm from the oscillating magnet, with its north pole pointing towards north as shown in figure. The frequency of oscillation is found to be increases to 60 oscillations per minute. Calculate the magnetic moment of this short bar magnet.[Horizontal component of the earth's magnetic field is 24 μT]
Answer» The frequency of oscillation of a bar magnet in an oscillation magnetometer in the earth's magnetic field is $40$ oscillations per $minute$ . A short bar magnet is placed to the north of the magnetometer, at a separation of $20 cm$ from the oscillating magnet, with its north pole pointing towards north as shown in figure. The frequency of oscillation is found to be increases to $60$ oscillations per $minute$ . Calculate the magnetic moment of this short bar magnet. [Horizontal component of the earth's magnetic field is $24 μ T$ ]

Discussion

13419.	33. A particle is placed on the top of a hemispherical shell of same mass, Shell is free to move on the smooth ground. If particle is given a gentie push and reaches to angular position q as shown in figure then for an obsenver fixed on a shell, ratio of reaction force exerted by shell to pseudo force (as observed from shell) acting on particle, is
Answer» 33. A particle is placed on the top of a hemispherical shell of same mass, Shell is free to move on the smooth ground. If particle is given a gentie push and reaches to angular position q as shown in figure then for an obsenver fixed on a shell, ratio of reaction force exerted by shell to pseudo force (as observed from shell) acting on particle, is

Discussion

13420.	Two thin long parallel wires separated by a distance b are carrying a current i amp each. The magnitude of the force per unit length exerted by one wire on the other is
Answer» Two thin long parallel wires separated by a distance b are carrying a current i amp each. The magnitude of the force per unit length exerted by one wire on the other is

Discussion

13421.	Velocity of sound in air at 47^° C is 360 m/s. What would be this velocity at 17^° C
Answer» Velocity of sound in air at 47^° C is 360 m/s. What would be this velocity at 17^° C

Discussion

13422.	A body is projected horizontally from top of A tall tower with velocity v. The velocity at the moment when horizontal and vertical displacement become equal
Answer» A body is projected horizontally from top of A tall tower with velocity v. The velocity at the moment when horizontal and vertical displacement become equal

Discussion

13423.	ACassegrain telescope uses two mirrors as shown in Fig. 9.33. Such atelescope is built with the mirrors 20 mm apart. If the radius ofcurvature of the large mirror is 220 mm and the small mirror is 140mm, where will the final image of an object at infinity be?
Answer» A Cassegrain telescope uses two mirrors as shown in Fig. 9.33. Such a telescope is built with the mirrors 20 mm apart. If the radius of curvature of the large mirror is 220 mm and the small mirror is 140 mm, where will the final image of an object at infinity be?

Discussion

13424.	(a) An electrostatic field line is a continuous curve. That is, a field line cannot have sudden breaks. Why not? (b) Explain why two field lines never cross each other at any point?
Answer» (a) An electrostatic field line is a continuous curve. That is, a field line cannot have sudden breaks. Why not? (b) Explain why two field lines never cross each other at any point?

13424.

(a) An electrostatic field line is a continuous curve. That is, a field line cannot have sudden breaks. Why not? (b) Explain why two field lines never cross each other at any point?

Answer»

(a) An
electrostatic field line is a continuous curve. That is, a field line
cannot have sudden breaks. Why not?

(b)
Explain why two field lines never cross each other at any point?

Discussion

13425.	150.A charge q, mass m moving with velocity v enters region of magnetic field B as shown in diagram. Assume magnetic field to be constant (within corresponding region) find deviation of charge and time spent in it by the charge
Answer» 150.A charge q, mass m moving with velocity v enters region of magnetic field B as shown in diagram. Assume magnetic field to be constant (within corresponding region) find deviation of charge and time spent in it by the charge

Discussion

13426.	The value of power dissipated across the Zener diode (Vz=15 V) connected in the circuit as shown in the figure is x×10−1 watts.The value of x to the nearest integer is
Answer» The value of power dissipated across the Zener diode $(V_{z} = 15 V)$ connected in the circuit as shown in the figure is $x \times 10^{- 1} watts$ . The value of $x$ to the nearest integer is

Discussion

13427.	Calculate the amount of work done in turning an electric dipole moment 2 x 10-8 m from its position of unstable equilibrium to the position of stable equilibrium in a uniform electric field intensity of 103 NC-
Answer» Calculate the amount of work done in turning an electric dipole moment 2 x 10-8 m from its position of unstable equilibrium to the position of stable equilibrium in a uniform electric field intensity of 103 NC-

Discussion

13428.	{ A particle is moving in parabolic path }x^2=y, with }}{ constant speed }v . When particle crosses origin, the }} radius of curvature at origin will be
Answer» { A particle is moving in parabolic path }x^2=y, with }}{ constant speed }v . When particle crosses origin, the }} radius of curvature at origin will be

Discussion

13429.	A ball of mass 2 kg is on a frictionless horizontal surface. It is attached to one end of a string and rotates about a fixed other end at an angular velocity 2 rev/sec. If the length of the string is doubled and angular velocity is halved, the tension in the string is equal to (Let initial tension be T0 )
Answer» A ball of mass $2 kg$ is on a frictionless horizontal surface. It is attached to one end of a string and rotates about a fixed other end at an angular velocity $2 rev/sec$ . If the length of the string is doubled and angular velocity is halved, the tension in the string is equal to (Let initial tension be $T_{0}$ )

Discussion

13430.	Determine and draw the graph of electric field due to infinitely large non-conducting sheet of thickness t and uniform volume charge density p as a function of distance x from its symmetry plane. (a) x=t/2
Answer» Determine and draw the graph of electric field due to infinitely large non-conducting sheet of thickness t and uniform volume charge density p as a function of distance x from its symmetry plane. (a) x<=t/2 (b) x>=t/2

Discussion

13431.	fraunhoffer diffraction simple explanation
Answer» fraunhoffer diffraction simple explanation

Discussion

13432.	A pendulum having time period equal to two seconds is called a seconds pendulum. Those used in pendulum clocks are of this type. Find the length of a seconds pendulum at a place where g=π2 m s−2.
Answer» A pendulum having time period equal to two seconds is called a seconds pendulum. Those used in pendulum clocks are of this type. Find the length of a seconds pendulum at a place where $g = π^{2} m s^{- 2} .$

Discussion

13433.	{ 10. A sphere of radius }R is having charge }Q uniformly distributed over it. The energy density of the electric }}{ field in the air, at a distance }(r>R) is given by (in }J/m^3) :
Answer» { 10. A sphere of radius }R is having charge }Q uniformly distributed over it. The energy density of the electric }}{ field in the air, at a distance }(r>R) is given by (in }J/m^3) :

Discussion

13434.	What curvature must be given to the bounding concave surface of refracting medium(3/2) for a virtual image at 40cm of an object in this medium at distance of 60cm. The adjoining medium is air.
Answer» What curvature must be given to the bounding concave surface of refracting medium(3/2) for a virtual image at 40cm of an object in this medium at distance of 60cm. The adjoining medium is air.

Discussion

13435.	The dimension formula of resultant when two quantities of dimensions [MLT−1] are added together, is
Answer» The dimension formula of resultant when two quantities of dimensions $[M L T^{- 1}]$ are added together, is

Discussion

13436.	At which angle, the intensity of transmitted light is maximum when a polaroid sheet is rotated between two crossed polaroids?
Answer» At which angle, the intensity of transmitted light is maximum when a polaroid sheet is rotated between two crossed polaroids?

Discussion

13437.	For a man walking horizontally with speed u, rain appears to hit him vertically down. When he makes his speed 'n' times, rain appears to hit him making an angle θ to the vertical. The original speed of rain is
Answer» For a man walking horizontally with speed u, rain appears to hit him vertically down. When he makes his speed 'n' times, rain appears to hit him making an angle $θ$ to the vertical. The original speed of rain is

Discussion

13438.	45. A horizontal force 3Mg/8 is applied at the top most of a cylinder of mass M ,length 2R and radius R as shown . If the cylinder remains at rest, distance of line of action of normal reaction from axis of cylinder is?
Answer» 45. A horizontal force 3Mg/8 is applied at the top most of a cylinder of mass M ,length 2R and radius R as shown . If the cylinder remains at rest, distance of line of action of normal reaction from axis of cylinder is?

Discussion

13439.	How to calculate spin only magnetic moment explain
Answer» How to calculate spin only magnetic moment explain

Discussion

13440.	A sample of gas is allowed to expand adiabatically. As a consequence its volume increases from 1 m3 to 32 m3 and temperature drops from 320 K to 80 K. How many degree of freedom are associated with the molecules of gas.
Answer» A sample of gas is allowed to expand adiabatically. As a consequence its volume increases from $1 m^{3}$ to $32 m^{3}$ and temperature drops from $320 K$ to $80 K$ . How many degree of freedom are associated with the molecules of gas.

Discussion

13441.	The ratio of velocities of diffusion of gases A and B is 1:4. If the ratio of their masses present in the mixture is 2:3, the ratio of their mole fractions is
Answer» The ratio of velocities of diffusion of gases $A$ and $B$ is $1 : 4$ . If the ratio of their masses present in the mixture is $2 : 3$ , the ratio of their mole fractions is

Discussion

13442.	When light rays approach the slits as shown in the figure below making an angle θ with the central axis, the number of maxima lying between O and the central maxima will be :
Answer» When light rays approach the slits as shown in the figure below making an angle $θ$ with the central axis, the number of maxima lying between $O$ and the central maxima will be :

Discussion

13443.	51 tuning fork are arranged in a series in such a way that each fork produce five beats/sec with neighbouring tunning fork. If frequency of last is six time of first then determine frequency of first, 11th, 17th, 27th, 33th last tunning fork
Answer» 51 tuning fork are arranged in a series in such a way that each fork produce five beats/sec with neighbouring tunning fork. If frequency of last is six time of first then determine frequency of first, 11th, 17th, 27th, 33th last tunning fork

Discussion

13444.	A particle is thrown from point B as shown in figure. At this moment of time, the angular speed of particle with respect to an axis passing through point A and perpendicular to plane of figure is
Answer» A particle is thrown from point B as shown in figure. At this moment of time, the angular speed of particle with respect to an axis passing through point A and perpendicular to plane of figure is

Discussion

13445.	A porter lifts a suitcase weighing 20 kg from the platform and puts it on his head 2.0 m above the platform. Calculate the work done by the porter on the suitcase.
Answer» A porter lifts a suitcase weighing $20 k g$ from the platform and puts it on his head $2.0 m$ above the platform. Calculate the work done by the porter on the suitcase.

Discussion

13446.	If at same pressure, the densities of two gases are ρ1 and ρ2 respectively,then the ratio of r.m.s. velocity of their molecules respectively are
Answer» If at same pressure, the densities of two gases are $ρ_{1}$ and $ρ_{2}$ respectively,then the ratio of r.m.s. velocity of their molecules respectively are

Discussion

13447.	why are the rays coming from an object at infinity considered as parallel to one another?
Answer» why are the rays coming from an object at infinity considered as parallel to one another?

Discussion

13448.	One mole of ideal monoatomic gas (γ=53) is mixed with one mole of diatomic gas (γ=75). What is γ for the mixture? γ denotes the ratio of specific heat at constant pressure, to that at constant volume.
Answer» One mole of ideal monoatomic gas $(γ = \frac{5}{3})$ is mixed with one mole of diatomic gas $(γ = \frac{7}{5})$ . What is $γ$ for the mixture? $γ$ denotes the ratio of specific heat at constant pressure, to that at constant volume.

Discussion

13449.	two equal charges q each are certain distance apart. What magnitude of charge Q should be kept at the mid point of the line joining the 2 charges such that the system is in equilibrium
Answer» two equal charges q each are certain distance apart. What magnitude of charge Q should be kept at the mid point of the line joining the 2 charges such that the system is in equilibrium

Discussion

13450.	A ball is placed on a smooth inclined plane of inclination θ=30∘ to the horizontal, the inclined plane is rotating at frequency 0.5 Hz about a vertical axis passing through its lower end. At what distance from the lower end does the ball remains at rest?
Answer» A ball is placed on a smooth inclined plane of inclination $θ = 30^{\circ}$ to the horizontal, the inclined plane is rotating at frequency $0.5$ $Hz$ about a vertical axis passing through its lower end. At what distance from the lower end does the ball remains at rest?

Discussion

Explore topic-wise InterviewSolutions in .

Consider the situation shown in figure (6-E2). Calculate (a) the acceleration of the 1.0 kg blocks, (b) the tension inthe string ocnecting the 1.0 kg blocks and (c) the tensionin th tring attached to 0.50 kg.

The average rotational kinetic energy for the diatomic gas molecules is (kB is Boltzmann constant and T is absolute temperature)

Derive an expression for electric field due to uniformly charged infinite plane sheet ?

How is an ammeter connected in a circuit?

99. A body of mass 5 kg is suspended by a spring balance on an inclined plane as shown in figure. The spring balance measure

A ball with initial velocity 1 m/s strikes a stationary ball of the same mass. If the final total kinetic energy is 50% greater than the original kinetic energy, the magnitude of the relative velocity between the two balls after collision (assuming collinear collision), is

Two conducting large plates P1 and P2 are placed near to each other at very small separation 'd'. The plate area of either face of plate is A. Now a charge +2Q is given to plate P1 and –Q to the plate P2 (neglect ends effects). Potential difference between the plates P1 and P2

A wave moves with speed 300 m/s on a wire which is under a tension of 500 N. Find how much the tension must be changed to increase the speed to 312 m/s?

why chandrayan2 mission launched from south give reason with the help of gravitation force concep

A parallel plate capacitor with air between the plates has a capacitance of 8 pF (1pF = 10–12 F). What will be the capacitance if the distance between the plates is reduced by half, and the space between them is filled with a substance of dielectric constant 6?

A force of 5 N acts on a particle along a direction making an angle of60∘ with vertical. Its vertical component be

50.Two concentric hollow spheres of radius r&R are shown. The charge on outer shell is Q. What charge should be given to the inner sphere so that the potential at any point outside the sphere is zero?

An ideal monoatomic gas is taken around the cycle ABCD as shown in figure below. Work done during the cycle is

Laws of motion

Points A and B are situated along the extended axis of 2 cm long bar magnet at a distance x and 2x cm respectively. From the pole nearer to the points, the ratio of the magnetic field at A and B will be

A system consists of a disc and square with equal surface mass density as shown in figure. The centre of mass is at the point of contact.The relation between L and R is L=(2π)nR.Then, find n. (Answer up to two decimal places)

Two thin long parallel wires separated by a distance b are carrying a current i amp each. The magnitude of the force per unit length exerted by one wire on the other is

Velocity of sound in air at 47^° C is 360 m/s. What would be this velocity at 17^° C

A body is projected horizontally from top of A tall tower with velocity v. The velocity at the moment when horizontal and vertical displacement become equal

ACassegrain telescope uses two mirrors as shown in Fig. 9.33. Such atelescope is built with the mirrors 20 mm apart. If the radius ofcurvature of the large mirror is 220 mm and the small mirror is 140mm, where will the final image of an object at infinity be?

(a) An electrostatic field line is a continuous curve. That is, a field line cannot have sudden breaks. Why not? (b) Explain why two field lines never cross each other at any point?

150.A charge q, mass m moving with velocity v enters region of magnetic field B as shown in diagram. Assume magnetic field to be constant (within corresponding region) find deviation of charge and time spent in it by the charge

The value of power dissipated across the Zener diode (Vz=15 V) connected in the circuit as shown in the figure is x×10−1 watts.The value of x to the nearest integer is

Calculate the amount of work done in turning an electric dipole moment 2 x 10-8 m from its position of unstable equilibrium to the position of stable equilibrium in a uniform electric field intensity of 103 NC-

{ A particle is moving in parabolic path }x^2=y, with }}{ constant speed }v . When particle crosses origin, the }} radius of curvature at origin will be

Determine and draw the graph of electric field due to infinitely large non-conducting sheet of thickness t and uniform volume charge density p as a function of distance x from its symmetry plane. (a) x=t/2

fraunhoffer diffraction simple explanation

A pendulum having time period equal to two seconds is called a seconds pendulum. Those used in pendulum clocks are of this type. Find the length of a seconds pendulum at a place where g=π2 m s−2.

{ 10. A sphere of radius }R is having charge }Q uniformly distributed over it. The energy density of the electric }}{ field in the air, at a distance }(r>R) is given by (in }J/m^3) :

What curvature must be given to the bounding concave surface of refracting medium(3/2) for a virtual image at 40cm of an object in this medium at distance of 60cm. The adjoining medium is air.

The dimension formula of resultant when two quantities of dimensions [MLT−1] are added together, is

At which angle, the intensity of transmitted light is maximum when a polaroid sheet is rotated between two crossed polaroids?

For a man walking horizontally with speed u, rain appears to hit him vertically down. When he makes his speed 'n' times, rain appears to hit him making an angle θ to the vertical. The original speed of rain is

45. A horizontal force 3Mg/8 is applied at the top most of a cylinder of mass M ,length 2R and radius R as shown . If the cylinder remains at rest, distance of line of action of normal reaction from axis of cylinder is?

How to calculate spin only magnetic moment explain

A sample of gas is allowed to expand adiabatically. As a consequence its volume increases from 1 m3 to 32 m3 and temperature drops from 320 K to 80 K. How many degree of freedom are associated with the molecules of gas.

The ratio of velocities of diffusion of gases A and B is 1:4. If the ratio of their masses present in the mixture is 2:3, the ratio of their mole fractions is

When light rays approach the slits as shown in the figure below making an angle θ with the central axis, the number of maxima lying between O and the central maxima will be :

51 tuning fork are arranged in a series in such a way that each fork produce five beats/sec with neighbouring tunning fork. If frequency of last is six time of first then determine frequency of first, 11th, 17th, 27th, 33th last tunning fork

A particle is thrown from point B as shown in figure. At this moment of time, the angular speed of particle with respect to an axis passing through point A and perpendicular to plane of figure is

A porter lifts a suitcase weighing 20 kg from the platform and puts it on his head 2.0 m above the platform. Calculate the work done by the porter on the suitcase.

If at same pressure, the densities of two gases are ρ1 and ρ2 respectively,then the ratio of r.m.s. velocity of their molecules respectively are

why are the rays coming from an object at infinity considered as parallel to one another?

One mole of ideal monoatomic gas (γ=53) is mixed with one mole of diatomic gas (γ=75). What is γ for the mixture? γ denotes the ratio of specific heat at constant pressure, to that at constant volume.

two equal charges q each are certain distance apart. What magnitude of charge Q should be kept at the mid point of the line joining the 2 charges such that the system is in equilibrium

A ball is placed on a smooth inclined plane of inclination θ=30∘ to the horizontal, the inclined plane is rotating at frequency 0.5 Hz about a vertical axis passing through its lower end. At what distance from the lower end does the ball remains at rest?