Tag: optics

Questions Related to optics

The refracting angle of a prism $60^{\mathrm{o}}$.The refractive index of the material of the prism is $\sqrt{\dfrac{7}{3}}$. The limiting angle of incidence of a ray that will be transmitted through the prism in this case will be :

problems on prism prism ray optics and optical instruments optics physics

  1. $30^{0}$

  2. $45^{\mathrm{o}}$

  3. $40^{\mathrm{o}}$

  4. $50^{\mathrm{o}}$

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Correct Option: A

If David is observing his image in plane mirror. The distance between the mirror and his image is 4 m. If he moves 1 m towards the mirror, then the distance between David and his image will be :

image formation by lens image formation by lenses ray optics and optical instruments optics physics

  1. 3 m

  2. 5 m

  3. 6 m

  4. 8 m

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Correct Option: C
Explanation:
Plane mirror produces erect image and is of same size and also at the same distance from the mirror as the object.

if he moves 1 m, distance of object from mirror= 3 m

distance of image from mirror= 3 m

distance between image and object =6 m.

When the reflecting or refracting rays do not actually intersect but appear to intersect when produced backwards, 

image formation by lens image formation by lenses ray optics and optical instruments optics physics

  1. a real image is formed

  2. a virtual image is formed

  3. either a real or a virtual image is formed

  4. neither a real nor a virtual image is formed

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Correct Option: B
Explanation:

A virtual image is formed when the refracting or reflecting rays do not actually intersect but appear to intersect when they are produced backwards.

The image which can be obtained on a screen is called

image formation by lens image formation by lenses ray optics and optical instruments optics physics

  1. a virtual image

  2. a real image

  3. either a real or a virtual image

  4. neither a real nor a virtual image

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Correct Option: B
Explanation:

The image which can be obtained on a screen is called a real image.

A virtual image is

image formation by lens image formation by lenses ray optics and optical instruments optics physics

  1. always erect

  2. either erect or inverted

  3. always inverted

  4. neither erect nor inverted

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Correct Option: A
Explanation:

A virtual image is always erect.

Comparing real and virtual images, we may say that

image formation by lens image formation by lenses ray optics and optical instruments optics physics

  1. real images can not be obtained on a screen and virtual images can be

  2. virtual images can not be obtained on a screen and real images can be

  3. both real and virtual images can be obtained on a screen

  4. neither real nor virtual images can be obtained on a screen

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Correct Option: B
Explanation:

Real images can be obtained on a screen. Virtual images can not be obtained on a screen.

A real image is formed by

image formation by lens image formation by lenses ray optics and optical instruments optics physics

  1. actual intersection of the refracting or reflecting rays

  2. imaginary intersection of the refracting or reflecting rays produced backwards

  3. either actual or imaginary intersection of the reflecting or refracting rays

  4. neither actual nor imaginary intersection of the reflecting or refracting rays

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Correct Option: A
Explanation:

When the refracting or reflecting rays actually intersect, a real image is formed.

A real image is

image formation by lens image formation by lenses ray optics and optical instruments optics physics

  1. always erect

  2. either erect or inverted

  3. always inverted

  4. neither erect nor inverted

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Correct Option: C
Explanation:

A real image is always inverted.

A thin convex lens of focal length $30.00\ cm$ forms an image $2.00\ cm$ high, of an object at infinity. A thin concave lens of focal length $20.00\ cm$ is placed $26.00\ cm$ from the convex lens on the side of the image. The height of the image now is

image formation by lens image formation by lenses ray optics and optical instruments optics physics

  1. $1.00\ cm$

  2. $1.25\ cm$

  3. $2.00\ cm$

  4. $2.50\ cm$

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Correct Option: D

A meter stick lies along the optic axis of a convex lens of focal length 40 cm its nearer end 60 cm from the mirror surface. How long is the image of stick?

image formation by lens image formation by lenses ray optics and optical instruments optics physics

  1. $200 cm$

  2. $\dfrac {200}{3} cm$

  3. $8 cm$

  4. $\dfrac{210}{6} cm$

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Correct Option: C