Tag: physics

Questions Related to physics

When a ray of light enters a medium of refractive index $\mu $ from air. It is observed that the angle of refraction is half the angle of incidence. The angle of incidence is :

physics light : reflection and refraction from plane surface principle of reversibility of path of light image formation by plane mirror refractive index

  1. $2 cos^{-1}(\frac{\mu }{2})$

  2. $ cos^{-1}(\frac{\mu }{2})$

  3. $2 cos^{-1}(\mu )$

  4. $2 sin^{-1}(\frac{\mu }{2})$

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Correct Option: C

Refractive index of diamond with respect to glass is $1.6$ and absolute refractive index of glass is $1.5$. Find out the absolute refractive index of diamond.

physics light : reflection and refraction from plane surface principle of reversibility of path of light image formation by plane mirror refractive index

  1. $1.06$

  2. $0.93$

  3. $2.4$

  4. $0.75$

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Correct Option: C
Explanation:
Given,

Refractive index of diamond with respect to glass, ${ _{ g }{ n } _{ d } } = 1.6$,

Absolute refractive index of glass, $n _{g} = 1.5$

Refractive index of diamond with respect to glass $= \dfrac {\text {Absolute refractive index of diamond}}{\text {Absolute refractive index of glass}}$

Therefore, absolute refractive index of diamond $=$ Refractive index of diamond with respect to glass $\times$ Absolute refractive index of glass $= 1.6 \times 1.5 = 2.4$

The refractive index of water is $\dfrac{4}{3}$ and of glass is $\dfrac{3}{2}$. What will be the refractive index of glass with respect to water?

physics light : reflection and refraction from plane surface principle of reversibility of path of light image formation by plane mirror refractive index

  1. $9.1$

  2. $2.623$

  3. $1.125$

  4. $1$

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Correct Option: C
Explanation:
refractive index of water =${ _{ a }{ \mu  } _{ w }= }\dfrac { 4 }{ 2 } $
refractive index of glass = ${ _{ a }{ \mu  } _{ g }= }\dfrac { 3 }{ 2 } $

then refractive index of glass w.r.t. water is
$ _{ w }{ \mu  } _{ g }= _{ a }{ \mu  } _{ g }\times \dfrac { 1 }{ _{ a }{ \mu  } _{ w } } $
${ _{ w }{ \mu  } _{ g }= _{ a }{ \mu  } _{ g }\times \dfrac { 1 }{ _{ a }{ \mu  } _{ w } } =\dfrac { 3 }{ 2 } \times \dfrac { 3 }{ 4 } =\dfrac { 9 }{ 8 } =1.125 }$

Option C is correct.


In its simplest interpretation the principle of reversibility is a corollary of __________ of the refraction  of light.

physics light : reflection and refraction from plane surface principle of reversibility of path of light image formation by plane mirror refractive index

  1. Snell's law

  2. Law of refraction

  3. Law of reflection

  4. None of these

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Correct Option: A
Explanation:

Principle of reversibility is a corollary of snells law-

Like with reflection, refraction also involves the angles that the incident ray and the refracted ray make with the normal to the surface at the point of refraction. Unlike reflection, refraction also depends on the media through which the light rays are traveling. This dependence is made explicit in Snell's Law via refractive indices, numbers which are constant for given media1.

Snell's Law is given in the following diagram.

Basic illustration of Snell's Law.

Principle of reversibility holds true for

physics light : reflection and refraction from plane surface principle of reversibility of path of light image formation by plane mirror refractive index

  1. Reflection

  2. Refraction

  3. Reflection and Refraction

  4. None of these

Show answer
Correct Option: C
Explanation:

Path of ray of light is reversible or light traces back it's path while traveling in reverse direction or a ray of light can pass in either direction along the same path.
So
Principle of reversibility holds true for both reflection and refraction.

The _____________ states that light will follow exactly the same path if its direction of travel is reversed. Fill the appropriate answer.

physics light : reflection and refraction from plane surface principle of reversibility of path of light image formation by plane mirror refractive index

  1. Newton's law of motion

  2. Laws of reflection

  3. Laws of refraction

  4. Principle of reversibility

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Correct Option: D
Explanation:

The principle of reversibility of light :-

Path of ray of light is reversible or light traces back it's path while travelling in reverse direction or a ray of light can pass in either direction along the same path

Note the directions of the arrow.

The beam of light travels back on the same path as it was traveling before the refraction and after the refraction after being encountered by the obstacle in the water.

Principle of reversibility can applied to 

physics light : reflection and refraction from plane surface principle of reversibility of path of light image formation by plane mirror refractive index

  1. Lens system

  2. Mirror system

  3. Lens and mirror system

  4. None of these

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Correct Option: C
Explanation:

Principle of reversibility can applied to both lens and mirror system,
Because the principle is followed by both-Path of ray of light is reversible or light traces back it's path while traveling in reverse direction or a ray of light can pass in either direction along the same path

The refractive index of gias with respect to air is $3/2$ and that of water with respect to air is $4/3$. What is the refractive index of glass with respect to water?

physics light : reflection and refraction from plane surface principle of reversibility of path of light image formation by plane mirror refractive index

  1. $9 : 8$

  2. $1 : 2$

  3. $2 : 1$

  4. $8 : 9$

Show answer
Correct Option: A
Explanation:

Given, 


Refractive index of glass=$\dfrac{3}{2}$


Refractive index of water=$\dfrac{4}{3}$

Refractive Index of glass with respect to water= $\dfrac{3/2}{4/3}$
                         =$\dfrac{9}{8}$

An electron having a charge e moves with a velocity v in X-direction. A magnetic field acts on it in Y-direction. The force on the electron acts in

physics magnetic effect of electric current fleming's left hand rule magnetic force magnetic force on a moving charge and current carrying wire

  1. positive direction of Y-axis

  2. negative direction of Y-axis

  3. positive direction of Z-axis

  4. negative direction of Z-axis

Show answer
Correct Option: D
Explanation:
As electron moving in positive x-direction, so the current  is moving in negative x-direction ( the direction of your middle finger) and the magnetic field acts on positive Y-direction ( the direction of your index finger) then thumb will be in negative Z-direction which is the direction of force. 

A positively charged particle falls vertically downwards. The horizontal component of earths magnetic field will deflect it towards

physics magnetic effect of electric current fleming's left hand rule magnetic force magnetic force on a moving charge and current carrying wire

  1. West

  2. East

  3. South

  4. North

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Correct Option: B