Tag: reflection of light in spherical mirrors

Questions Related to reflection of light in spherical mirrors

A $10\mathrm { mm }$ long awl pin is placed vertically In front of a concave mirror. A $5\ mm$ long image of the awl pin is formed at $30\mathrm { cm }$ in front of the mirror, The focal length of this mirror is 

physics reflection of light in spherical mirrors focus and focal length spherical mirror formula and magnification reflection of light by curved surfaces

  1. $- 30 \mathrm { cm }$

  2. $- 20 \mathrm { cm }$

  3. $- 40 \mathrm { cm }$

  4. $- 60 \mathrm { cm }$

Show answer
Correct Option: B

A point object is placed on principal axis of concave mirror of radius of curvature 10 cm at a distance 21 cm from pole of the mirror.  A glass slab of thickness 3 cm and refractive index 1.5 is placed between object and mirror $.$ Find the imaged position of the image formed. 

physics reflection of light in spherical mirrors focus and focal length spherical mirror formula and magnification reflection of light by curved surfaces

  1. 4

  2. 3

  3. 16.5

  4. 5

Show answer
Correct Option: C

A converging bundle of light rays in the shape of cone with a vertex angle of 45 falls on a circular diaphragm of 20 cm diameter. A lens with power 5 D is fixed in the diaphragm. Diameter of face of lens is equal to that of diaphragm. If the vertex angle of new cone is 

physics reflection of light in spherical mirrors focus and focal length spherical mirror formula and magnification reflection of light by curved surfaces

  1. $
    \cfrac { 3 d } { 4 }
    $

  2. $
    \cfrac { 5 d } { 4 }
    $

  3. $
    2 d
    $

  4. $
    \cfrac { 3 } { 2 } d
    $

Show answer
Correct Option: B

All the following statements are correct except

physics reflection of light in spherical mirrors focus and focal length spherical mirror formula and magnification reflection of light by curved surfaces

  1. The magnification produced by a convex mirror is always less than one.

  2. A virtual, crect , same-size image can be obtained by using a plane mirror.

  3. A virtual, crect , magnified image can be formed by using a convex mirror.

  4. A virtual, inverted , same-sized image can be formed by using a convex mirror.

Show answer
Correct Option: A

If a spherical mirror is immersed in a liquid its focal length

physics reflection of light in spherical mirrors focus and focal length spherical mirror formula and magnification reflection of light by curved surfaces

  1. Decreases

  2. Remains same

  3. Increases

  4. Increases and Decreases

Show answer
Correct Option: C

The suns diameter is $1.4\times { 10 }^{ 9 }m$ and its distance from the earth is ${ 10 }^{ 11 }m$. The diameter of its image, formed by a convex mirror of focal length 2m will

physics reflection of light in spherical mirrors focus and focal length spherical mirror formula and magnification reflection of light by curved surfaces

  1. 0.7 cm

  2. 1.4 cm

  3. 2.8 cm

  4. 10 cm

Show answer
Correct Option: C

The distance of real object when a concave mirror produces a real image of magnification $'m'$ is ($f$ is focal length)

physics reflection of light in spherical mirrors focus and focal length spherical mirror formula and magnification reflection of light by curved surfaces

  1. $\left(\frac{m - 1}{m}\right) f$

  2. $\left(\frac{m + 1}{m}\right) f$

  3. $(m-1)f$

  4. $(m+1)f$

Show answer
Correct Option: D

Converging rays are incident on a convex spherical mirror so that their extensions intersect  $30 cm$  behind the mirror on the optical axis. The reflected rays form a diverging beam, so that their extensions intersect the optical axis  $1.2 m$  from the mirror. The focal length of the mirror is

physics reflection of light in spherical mirrors focus and focal length spherical mirror formula and magnification reflection of light by curved surfaces

  1. $40{ cm }$

  2. $60{ cm }$

  3. $30{ cm }$

  4. $24{ cm }$

Show answer
Correct Option: A

Magnification produced by a rear view mirror fitted in vehicles

physics reflection of light in spherical mirrors focus and focal length spherical mirror formula and magnification reflection of light by curved surfaces

  1. is less than one

  2. is more than one

  3. is equal to one

  4. can be more than or less than one depending upon the position of the object in front of it.

Show answer
Correct Option: A

A concave mirror of radius of curvature 40 cm forms an image of an object placed on the principal axis at a distance 45 cm in front of it. Now if the system (including object) is completely immersed in water $(\mu=1.33)$, then:

physics reflection of light in spherical mirrors focus and focal length spherical mirror formula and magnification reflection of light by curved surfaces

  1. the image will shift towards the mirror.

  2. the magnification will reduce.

  3. the image will shift away from the mirror and magnification will increase.

  4. the position of the image and magnification will not change.

Show answer
Correct Option: D
Explanation:

Mirror operates on the principle of Laws of reflection. 

Therefore, focal length does not depend upon the medium and object distance is also unchanged, so their will be no change in the image distance, correspondingly magnification will also remain unchanged.