50278 + Interview Questions in Physics

1.	A body is executing SHM with amplitude a and time period T. The ratio of KE and PE when displacement from the equilibrium position is half the amplitude
Answer» A body is executing SHM with amplitude a and time period T. The ratio of KE and PE when displacement from the equilibrium position is half the amplitude

Discussion

2.	Young's double slit experiment is carried out by using green, red and blue lihgt, one color at a time. The fringe widths recorded are βB,βR and βB respecitvley. Then,
Answer» Young's double slit experiment is carried out by using green, red and blue lihgt, one color at a time. The fringe widths recorded are $β_{B}, β_{R}$ and $β_{B}$ respecitvley. Then,

Discussion

3.	A flat coil of 500 turns, each of area 50 cm2, rotates in a uniform magnetic field of 0.1 Wb/m2 about an axis normal to the field at an angular speed of 150 rad/s. (Initially magnetic field was along the area vector of the field). The coil has a resistance of 15 Ω. Maximum induced current in the coil is
Answer» A flat coil of $500$ turns, each of area $50 c m^{2}$ , rotates in a uniform magnetic field of $0.1 W b / m^{2}$ about an axis normal to the field at an angular speed of $150 r a d / s$ . (Initially magnetic field was along the area vector of the field). The coil has a resistance of $15 Ω$ . Maximum induced current in the coil is

Discussion

4.	17. Q. If a particle moves in a circle of radius r with decreasing speed and F is the force acting on that particle, then- (1) Angle between F and and r is 90^° (2) Angle between F and r is 180 (3) Angle between F and r is between 90^° and 180^° (3) Angle between F and r is between 0^° and 90^°
Answer» 17. Q. If a particle moves in a circle of radius r with decreasing speed and F is the force acting on that particle, then- (1) Angle between F and and r is 90^° (2) Angle between F and r is 180 (3) Angle between F and r is between 90^° and 180^° (3) Angle between F and r is between 0^° and 90^°

Discussion

5.	Motional emf explanation
Answer» Motional emf explanation

Discussion

6.

Three blocks of masses M1,M2 and M are arranged as shown in the figure. All the surfaces are frictionless and string is inextensible. Pulleys are light. A constant force F is applied on block of mass M1. Pulleys and string are light. Part of the string connecting both pulleys is vertical and part of the string connecting pulleys with masses M1 and M2 are horizontal.(P) Acceleration of mass M1(1) FM2(Q) Acceleration of mass M2(2) FM1+M2(R) Acceleration of mass M(3) zero(S) Tension in the string(4) M2FM1+M2

Answer»

Three blocks of masses $M_{1}, M_{2}$ and $M$ are arranged as shown in the figure. All the surfaces are frictionless and string is inextensible. Pulleys are light. A constant force $F$ is applied on block of mass $M_{1}$ . Pulleys and string are light. Part of the string connecting both pulleys is vertical and part of the string connecting pulleys with masses $M_{1} and M_{2}$ are horizontal.

(P) Acceleration of mass $M_{1}$	(1) $\frac{F}{M_{2}}$
(Q) Acceleration of mass $M_{2}$	(2) $\frac{F}{M_{1} + M_{2}}$
(R) Acceleration of mass $M$	(3) zero
(S) Tension in the string	(4) $\frac{M_{2} F}{M_{1} + M_{2}}$

Discussion

7.	If I throw a ball upwards to a certain height in an accelerating train, will it end up in my hand or not? Explain
Answer» If I throw a ball upwards to a certain height in an accelerating train, will it end up in my hand or not? Explain

Discussion

8.	Maghetic force acting on the charged particle projected perpendiculat to magnetic field isproportional to v, where v^{n^{}} is the speed. Find n
Answer» Maghetic force acting on the charged particle projected perpendiculat to magnetic field isproportional to v, where v^{n^{}} is the speed. Find n

Discussion

9.	A 10 kg ball attached at the end of a rigid massless rod of length 1 m rotates at constant speed in a horizontal circle of radius 0.5 m with a period of 1.58 s, as shown in the figure. The force exerted by the rod on the ball is[Take g=10 m/s2]
Answer» A $10 kg$ ball attached at the end of a rigid massless rod of length $1 m$ rotates at constant speed in a horizontal circle of radius $0.5 m$ with a period of $1.58 s$ , as shown in the figure. The force exerted by the rod on the ball is [Take $g = 10 {m/s}^{2}$ ]

Discussion

10.	If u1 and u2 are the units selected in two systems of unit of any physical quantity and n1 and n2 are their numerical values then
Answer» If $u_{1}$ and $u_{2}$ are the units selected in two systems of unit of any physical quantity and $n_{1}$ and $n_{2}$ are their numerical values then

Discussion

11.	An electric dipole gas the magnitude of its charge as q and its dipole moment as p. Its placed in a uniform electric fieldE.If its dipole moment is along the direction of the field,the force on it is?
Answer» An electric dipole gas the magnitude of its charge as q and its dipole moment as p. Its placed in a uniform electric fieldE.If its dipole moment is along the direction of the field,the force on it is?

Discussion

12.	The distance of separation between the 3rd and 2nd orbit in the hydrogen atom is:
Answer» The distance of separation between the $3^{r d}$ and $2^{n d}$ orbit in the hydrogen atom is:

Discussion

13.	An astronomical telescope has a large aperture to:
Answer» An astronomical telescope has a large aperture to:

Discussion

14.	Consider a particle moving in simple harmonic motion according to the equation x=2.0 cos(to π t+tan−1 0.75) where x is in centimetre and t in second. The motion is started at t=0. (a) When does the particle come to rest for the first time ? (b) When does the acceleration have its maximum magnitude for the first time ? (c) When does the particle come to rest for the second time ?
Answer» Consider a particle moving in simple harmonic motion according to the equation $x = 2.0 c o s (t o π t + t a n^{- 1} 0.75)$ where x is in centimetre and t in second. The motion is started at $t = 0.$ (a) When does the particle come to rest for the first time ? (b) When does the acceleration have its maximum magnitude for the first time ? (c) When does the particle come to rest for the second time ?

14.

Consider a particle moving in simple harmonic motion according to the equation x=2.0 cos(to π t+tan−1 0.75) where x is in centimetre and t in second. The motion is started at t=0. (a) When does the particle come to rest for the first time ? (b) When does the acceleration have its maximum magnitude for the first time ? (c) When does the particle come to rest for the second time ?

Answer»

Consider a particle moving in simple harmonic motion according to the equation

$x = 2.0 c o s (t o π t + t a n^{- 1} 0.75)$

where x is in centimetre and t in second. The motion is started at $t = 0.$ (a) When does the particle come to rest for the first time ? (b) When does the acceleration have its maximum magnitude for the first time ? (c) When does the particle come to rest for the second time ?

Discussion

15.	Mass = ? Volume = 190m³ Density = 4kg/m3
Answer» Mass = ? Volume = 190m³ Density = 4kg/m3

15.

Mass = ? Volume = 190m³ Density = 4kg/m3

Answer»

Mass = ?

Volume = 190m³

Density = 4kg/m3

Discussion

16.	The conducting spheres of radius r and 2r at very large separation. Each sphere is having charge Q. These spheres are connected with a conducting wire of resistance R. Then, the current flowing in the wire at t=2μs. (Where r = 30cm, R=90kΩ and Q=10 μC))
Answer» The conducting spheres of radius r and 2r at very large separation. Each sphere is having charge Q. These spheres are connected with a conducting wire of resistance R. Then, the current flowing in the wire at $t = 2 μ s$ . (Where r = 30cm, $R = 90 k Ω$ and $Q = 10 μ C)$ )

Discussion

17.	A flatcar of mass m0=20 kg is moving to the right due to a constant horizontal force F=10 N. Sand spills on the flatcar from a stationary hopper. The velocity of loading is constant and equal to μ=1 kg/s. Find the acceleration of the flatcar after t=20 s.
Answer» A flatcar of mass $m_{0} = 20 kg$ is moving to the right due to a constant horizontal force $F = 10 N$ . Sand spills on the flatcar from a stationary hopper. The velocity of loading is constant and equal to $μ = 1 kg/s$ . Find the acceleration of the flatcar after $t = 20 s$ .

Discussion

18.	Force between two identical charge placed at a distance of r in vaccum is F now a slab of dielectric of dielectric constant K=4 is inserted between the two charge the thickness of slab is r/2 then find new force between two charge
Answer» Force between two identical charge placed at a distance of r in vaccum is F now a slab of dielectric of dielectric constant K=4 is inserted between the two charge the thickness of slab is r/2 then find new force between two charge

Discussion

19.	At what distance from O the image for the converging beam after refraction through the curved surface will be formed?
Answer» At what distance from $O$ the image for the converging beam after refraction through the curved surface will be formed?

Discussion

20.	The time period of revolution of e− in ground state orbit of hydrogen atom is Tλ, then frequency of e− in second excited state of Li++ ion is
Answer» The time period of revolution of $e^{-}$ in ground state orbit of hydrogen atom is $T_{λ}$ , then frequency of $e^{-}$ in second excited state of $L i^{+ +}$ ion is

Discussion

21.	A uniform simply supported beam AB as shown in the figure below is subjected to a clockwise moment of 100 kN. at end A.The rotation at joint B is ____ radians.0.0125
Answer» A uniform simply supported beam AB as shown in the figure below is subjected to a clockwise moment of 100 kN. at end A. The rotation at joint B is ____ radians. 0.0125

Discussion

22.	A 1.0 mH inductance, a10μF capacitance and a 5.0 ohm resistance are connected series to an a.c. source. It is found that inductor and the capacitor show equal reactance. The reactance should be nearest to:
Answer» A 1.0 mH inductance, a10μF capacitance and a 5.0 ohm resistance are connected series to an a.c. source. It is found that inductor and the capacitor show equal reactance. The reactance should be nearest to:

Discussion

23.	A given amount of gas is heated till the volume and pressure both increase by 2% each.the percentage change in temperature of the gas is nearly?
Answer» A given amount of gas is heated till the volume and pressure both increase by 2% each.the percentage change in temperature of the gas is nearly?

Discussion

24.	A light thread is wound on a disk of mass m and other end of thread is connected to a block of mass m, which is placed on a rough ground as shown in diagram. Find the minimum value of coefficient of friction for which block remain at rest.
Answer» A light thread is wound on a disk of mass $m$ and other end of thread is connected to a block of mass $m$ , which is placed on a rough ground as shown in diagram. Find the minimum value of coefficient of friction for which block remain at rest.

Discussion

25.	A ball is dropped on the floor from a height of 20m . It rebounds to a height of 10 m . If the ball is in contact with the floor for 0.1 seconds, what is the average acceleration during contact?
Answer» A ball is dropped on the floor from a height of 20m . It rebounds to a height of 10 m . If the ball is in contact with the floor for 0.1 seconds, what is the average acceleration during contact?

Discussion

26.	As you have learnt in the text, a geostationary satellite orbits the earth at a height of nearly 36,000 km from the surface of the earth. What is the potential due to earth’s gravity at the site of this satellite ? (Take the potential energy at infinity to be zero). Mass of the earth = 6.0×1024 kg, radius = 6400 km.
Answer» As you have learnt in the text, a geostationary satellite orbits the earth at a height of nearly 36,000 km from the surface of the earth. What is the potential due to earth’s gravity at the site of this satellite ? (Take the potential energy at infinity to be zero). Mass of the earth = 6.0×1024 kg, radius = 6400 km.

Discussion

27.	35.Time of descent formula
Answer» 35.Time of descent formula

Discussion

28.	A block of mass 10 kg rests on a horizontal floor. The acceleraton due to gravity is 9.81ms2 . The coefficient of static friction between the floor and the block is 0.2. A horizontal forcce of 10 N is applied on the block as shown in the figure. The magnitude of force of friction (in N) on the block is
Answer» A block of mass 10 kg rests on a horizontal floor. The acceleraton due to gravity is $9.81 \frac{m}{s^{2}}$ . The coefficient of static friction between the floor and the block is 0.2. A horizontal forcce of 10 N is applied on the block as shown in the figure. The magnitude of force of friction (in N) on the block is

Discussion

29.	A ball of mass 2 kg, travelling with a velocity 2^i+3^j+4^k m/s receives an impulse of 4^i+2^j N-s. What is the velocity of the ball immediately after the impulse is imparted?
Answer» A ball of mass $2 kg$ , travelling with a velocity $2^i + 3^j + 4^k m/s$ receives an impulse of $4^i + 2^j N-s$ . What is the velocity of the ball immediately after the impulse is imparted?

Discussion

30.	What does the slope of the coloured lines express in this position time graph.
Answer» What does the slope of the coloured lines express in this position time graph.

Discussion

31.	The ratio of electric force and gravitational force between a proton and an electron isK e^2 / G memp ≅ 2.4 × 10^39
Answer» The ratio of electric force and gravitational force between a proton and an electron is K e^2 / G memp ≅ 2.4 × 10^39

Discussion

32.	The area of the triangle formed by 2^i+^j and ^i+^j is
Answer» The area of the triangle formed by $2^i +^j$ and $^i +^j$ is

Discussion

33.	A spring is stretched by 5 cm by a force 10 N. The time period of the oscillations when a mass of 2 kg is suspended by it is
Answer» A spring is stretched by $5 cm$ by a force $10 N$ . The time period of the oscillations when a mass of $2 kg$ is suspended by it is

Discussion

34.	Valence bond theory was proposed by
Answer» Valence bond theory was proposed by

Discussion

35.	The nucleus AZY goes through gamma decay. What shall be the product?
Answer» The nucleus $_{Z}^{A} Y$ goes through gamma decay. What shall be the product?

Discussion

36.	a particle is projected from ground at angle theta with horizontal with speed u the ratio of radius of curvature of its trajectory at point of projection to radius of curvature at max height is
Answer» a particle is projected from ground at angle theta with horizontal with speed u the ratio of radius of curvature of its trajectory at point of projection to radius of curvature at max height is

Discussion

37.	An electron in a hydrogen atom makes a transition from n=n1 and n=n2 The time period of the electron in the initial state is eight times that in the final state. The possible values of n1 and n2 are
Answer» An electron in a hydrogen atom makes a transition from $n = n_{1}$ and $n = n_{2}$ The time period of the electron in the initial state is eight times that in the final state. The possible values of $n_{1} and n_{2}$ are

Discussion

38.	Two particles of same mass are performing simple harmonic oscillation along the y−axis whose displacement time graphs are shown. If E1 and E2 are their energies of oscillation, then
Answer» Two particles of same mass are performing simple harmonic oscillation along the $y -$ axis whose displacement time graphs are shown. If $E_{1}$ and $E_{2}$ are their energies of oscillation, then

Discussion

39.	State relationship between Celsius and Fahrenheit scale ?
Answer» State relationship between Celsius and Fahrenheit scale ?

Discussion

40.	a boat streams in a river with velocity 2i cap+5j cap with respect to ground.the river water flows with a velocity of -3icap-4jcap with respect to the ground. what is the relative velocity of boat w.r.t. river water ?
Answer» a boat streams in a river with velocity 2i cap+5j cap with respect to ground.the river water flows with a velocity of -3icap-4jcap with respect to the ground. what is the relative velocity of boat w.r.t. river water ?

Discussion

41.	Two balls A and B are thrown vertically upwards from the same location on the surface of the earth with velocities 2 \sqrt{gR÷} and \sqrt{2gR÷3} respectively, whre R is the radius of the earth and g is the acceleration due to gravity on the surface of the earth. determine the ratio of the maximum height attained by A to that attained by B.
Answer» Two balls A and B are thrown vertically upwards from the same location on the surface of the earth with velocities 2 \sqrt{gR÷} and \sqrt{2gR÷3} respectively, whre R is the radius of the earth and g is the acceleration due to gravity on the surface of the earth. determine the ratio of the maximum height attained by A to that attained by B.

Discussion

42.	Two liquids of densities ρ1 and ρ2 (ρ2=2ρ1) are filled up behind a square wall of side 10 m as shown in figure. Each liquid has a height of 5 m. The ratio of the forces due to these liquids exerted on upper part MN to that at the lower part NO is (Assume that the liquids are not mixing)
Answer» Two liquids of densities $ρ_{1} and ρ_{2} (ρ_{2} = 2 ρ_{1})$ are filled up behind a square wall of side $10 m$ as shown in figure. Each liquid has a height of $5 m$ . The ratio of the forces due to these liquids exerted on upper part $M N$ to that at the lower part $N O$ is (Assume that the liquids are not mixing)

Discussion

43.	32.In case of flurine, oxygen and nitrogen atoms the maximum covalency is one, three, four respectively. Explain how ?
Answer» 32.In case of flurine, oxygen and nitrogen atoms the maximum covalency is one, three, four respectively. Explain how ?

Discussion

44.	A body is thrown with velocity 20 m/s at an angle of 60o with the horizontal. The time gap (in s) between the two positions of body where velocity of body makes an angle of 30o with horizontal is
Answer» A body is thrown with velocity $20 m / s$ at an angle of $60^{o}$ with the horizontal. The time gap (in $s$ ) between the two positions of body where velocity of body makes an angle of $30^{o}$ with horizontal is

Discussion

45.	State Biot – Savart law. Deduce the expression for the magnetic field at a point on the axis of a current carrying circular loop of radius ‘R’ at a distance ‘x’ from the centre. Hence, write the magnetic field at the centre of a loop.
Answer» State Biot – Savart law. Deduce the expression for the magnetic field at a point on the axis of a current carrying circular loop of radius ‘R’ at a distance ‘x’ from the centre. Hence, write the magnetic field at the centre of a loop.

Discussion

46.	64.A flight was scheduled to go from Delhi to mumbai covering 1200 km, but due to engine problem, its speed was reduced to 3/4th of the original. Therefore, it reachedthe destination 60 min late. What is the original speed and original time of journey?
Answer» 64.A flight was scheduled to go from Delhi to mumbai covering 1200 km, but due to engine problem, its speed was reduced to 3/4th of the original. Therefore, it reachedthe destination 60 min late. What is the original speed and original time of journey?

Discussion

47.	A light of wavelength 6000 A∘ and frequency 5×1014 Hz in air enters a medium with refractive index 1.5. Inside the medium its frequency (in Hz) and wavelength (in A∘) respectively are
Answer» A light of wavelength $6000 A^{\circ}$ and frequency $5 \times 10^{14} H z$ in air enters a medium with refractive index 1.5. Inside the medium its frequency (in Hz) and wavelength (in $A^{\circ}$ ) respectively are

Discussion

48.	A particle of mass m moves with constant speed v on a circular path of radius r. Find magnitude of average force on it in half revoulation.
Answer» A particle of mass m moves with constant speed v on a circular path of radius r. Find magnitude of average force on it in half revoulation.

Discussion

49.	For a normal eye, the cornea of the eye provides a converging power of 40 D, and the least converging power of the eye lens behind the cornea is 20 D. Using this information, the distance between the retina and the cornea-eye lens can be estimated to be -
Answer» For a normal eye, the cornea of the eye provides a converging power of $40 D$ , and the least converging power of the eye lens behind the cornea is $20 D$ . Using this information, the distance between the retina and the cornea-eye lens can be estimated to be -

Discussion

50.	Light from a sodium vapor lamp is made to pass through two polaroids placed one after the other in the path of light. Taking the intensity of the incident light as 100%, the intensity of the light, coming out of second polarizer, can be varied in the range,
Answer» Light from a sodium vapor lamp is made to pass through two polaroids placed one after the other in the path of light. Taking the intensity of the incident light as $100 %$ , the intensity of the light, coming out of second polarizer, can be varied in the range,

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

A body is executing SHM with amplitude a and time period T. The ratio of KE and PE when displacement from the equilibrium position is half the amplitude

Young's double slit experiment is carried out by using green, red and blue lihgt, one color at a time. The fringe widths recorded are βB,βR and βB respecitvley. Then,

Motional emf explanation

If I throw a ball upwards to a certain height in an accelerating train, will it end up in my hand or not? Explain

Maghetic force acting on the charged particle projected perpendiculat to magnetic field isproportional to v, where v^{n^{}} is the speed. Find n

A 10 kg ball attached at the end of a rigid massless rod of length 1 m rotates at constant speed in a horizontal circle of radius 0.5 m with a period of 1.58 s, as shown in the figure. The force exerted by the rod on the ball is[Take g=10 m/s2]

If u1 and u2 are the units selected in two systems of unit of any physical quantity and n1 and n2 are their numerical values then

An electric dipole gas the magnitude of its charge as q and its dipole moment as p. Its placed in a uniform electric fieldE.If its dipole moment is along the direction of the field,the force on it is?

The distance of separation between the 3rd and 2nd orbit in the hydrogen atom is:

An astronomical telescope has a large aperture to:

Mass = ? Volume = 190m³ Density = 4kg/m3

The conducting spheres of radius r and 2r at very large separation. Each sphere is having charge Q. These spheres are connected with a conducting wire of resistance R. Then, the current flowing in the wire at t=2μs. (Where r = 30cm, R=90kΩ and Q=10 μC))

A flatcar of mass m0=20 kg is moving to the right due to a constant horizontal force F=10 N. Sand spills on the flatcar from a stationary hopper. The velocity of loading is constant and equal to μ=1 kg/s. Find the acceleration of the flatcar after t=20 s.

Force between two identical charge placed at a distance of r in vaccum is F now a slab of dielectric of dielectric constant K=4 is inserted between the two charge the thickness of slab is r/2 then find new force between two charge

At what distance from O the image for the converging beam after refraction through the curved surface will be formed?

The time period of revolution of e− in ground state orbit of hydrogen atom is Tλ, then frequency of e− in second excited state of Li++ ion is

A uniform simply supported beam AB as shown in the figure below is subjected to a clockwise moment of 100 kN. at end A.The rotation at joint B is ____ radians.0.0125

A 1.0 mH inductance, a10μF capacitance and a 5.0 ohm resistance are connected series to an a.c. source. It is found that inductor and the capacitor show equal reactance. The reactance should be nearest to:

A given amount of gas is heated till the volume and pressure both increase by 2% each.the percentage change in temperature of the gas is nearly?

A light thread is wound on a disk of mass m and other end of thread is connected to a block of mass m, which is placed on a rough ground as shown in diagram. Find the minimum value of coefficient of friction for which block remain at rest.

A ball is dropped on the floor from a height of 20m . It rebounds to a height of 10 m . If the ball is in contact with the floor for 0.1 seconds, what is the average acceleration during contact?

35.Time of descent formula

A ball of mass 2 kg, travelling with a velocity 2^i+3^j+4^k m/s receives an impulse of 4^i+2^j N-s. What is the velocity of the ball immediately after the impulse is imparted?

What does the slope of the coloured lines express in this position time graph.

The ratio of electric force and gravitational force between a proton and an electron isK e^2 / G memp ≅ 2.4 × 10^39

The area of the triangle formed by 2^i+^j and ^i+^j is

A spring is stretched by 5 cm by a force 10 N. The time period of the oscillations when a mass of 2 kg is suspended by it is

Valence bond theory was proposed by

The nucleus AZY goes through gamma decay. What shall be the product?

a particle is projected from ground at angle theta with horizontal with speed u the ratio of radius of curvature of its trajectory at point of projection to radius of curvature at max height is

An electron in a hydrogen atom makes a transition from n=n1 and n=n2 The time period of the electron in the initial state is eight times that in the final state. The possible values of n1 and n2 are

Two particles of same mass are performing simple harmonic oscillation along the y−axis whose displacement time graphs are shown. If E1 and E2 are their energies of oscillation, then

State relationship between Celsius and Fahrenheit scale ?

a boat streams in a river with velocity 2i cap+5j cap with respect to ground.the river water flows with a velocity of -3icap-4jcap with respect to the ground. what is the relative velocity of boat w.r.t. river water ?

Two liquids of densities ρ1 and ρ2 (ρ2=2ρ1) are filled up behind a square wall of side 10 m as shown in figure. Each liquid has a height of 5 m. The ratio of the forces due to these liquids exerted on upper part MN to that at the lower part NO is (Assume that the liquids are not mixing)

32.In case of flurine, oxygen and nitrogen atoms the maximum covalency is one, three, four respectively. Explain how ?

A body is thrown with velocity 20 m/s at an angle of 60o with the horizontal. The time gap (in s) between the two positions of body where velocity of body makes an angle of 30o with horizontal is

State Biot – Savart law. Deduce the expression for the magnetic field at a point on the axis of a current carrying circular loop of radius ‘R’ at a distance ‘x’ from the centre. Hence, write the magnetic field at the centre of a loop.

64.A flight was scheduled to go from Delhi to mumbai covering 1200 km, but due to engine problem, its speed was reduced to 3/4th of the original. Therefore, it reachedthe destination 60 min late. What is the original speed and original time of journey?

A light of wavelength 6000 A∘ and frequency 5×1014 Hz in air enters a medium with refractive index 1.5. Inside the medium its frequency (in Hz) and wavelength (in A∘) respectively are

A particle of mass m moves with constant speed v on a circular path of radius r. Find magnitude of average force on it in half revoulation.

For a normal eye, the cornea of the eye provides a converging power of 40 D, and the least converging power of the eye lens behind the cornea is 20 D. Using this information, the distance between the retina and the cornea-eye lens can be estimated to be -

Light from a sodium vapor lamp is made to pass through two polaroids placed one after the other in the path of light. Taking the intensity of the incident light as 100%, the intensity of the light, coming out of second polarizer, can be varied in the range,