Tag: reflection of light at curved surfaces

Questions Related to reflection of light at curved surfaces

Mark the incorrect statement regarding mirror formula.

physics reflection of light at curved surfaces the mirror formula derivation of formula for curved mirrors mirror formula and magnification

  1. Values of known and unknown parameters can be used with their proper signs

  2. Sign of unknown parameter comes of its own after calculation

  3. Mirror formula is applicable for both concave and convex mirrors

  4. All

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Correct Option: A
Explanation:

The values of known parameter should be used with their proper sign convention. No sign should be attached to the unknown parameter during calculation. Its sign will come of its own after calculation.

The relation among u, v and f for a mirror is

physics reflection of light at curved surfaces the mirror formula derivation of formula for curved mirrors mirror formula and magnification

  1. $f = uv/(u+v)$

  2. $v = fu/(u+f)$

  3. $u = fv/(f+v)$

  4. All of these

Show answer
Correct Option: A
Explanation:

According to mirror equation.

$\cfrac{1}{f} = \cfrac{1}{u}+ \cfrac{1}{v}$
$\cfrac{1}{f} = \cfrac{u+v}{uv}$
$f = \cfrac{uv}{u+v}$

Similarly,
$v = \cfrac{fu}{u-f}$
$u = \cfrac{fv}{v-f}$

The relation among $u,v$ and $f$ for a mirror is:

physics reflection of light at curved surfaces the mirror formula derivation of formula for curved mirrors mirror formula and magnification

  1. $f=uv(u+v)$

  2. $v=fu(u+f)$

  3. $u=fv(f+v)$

  4. None of these

Show answer
Correct Option: D
Explanation:

from mirror formula

              $\dfrac { 1 }{ v } +\dfrac { 1 }{ u } =\dfrac { 1 }{ f } $
              $\Rightarrow \quad \boxed { f=\dfrac { uv }{ u+v }  } $
and
          $1+\dfrac { v }{ u } =\dfrac { v }{ f } \Rightarrow \boxed { u=\dfrac { fv }{ f-v }  } $

A object moving at a speed of $5$ m/s towards a concave mirror of focal length $f=1$m is at a distance of $9$m. The average speed of the image is?

physics reflection of light at curved surfaces the mirror formula derivation of formula for curved mirrors mirror formula and magnification

  1. $\dfrac{1}{5}$ m/s

  2. $\dfrac{1}{10}$ m/s

  3. $\dfrac{4}{5}$ m/s

  4. $\dfrac{2}{5}$ m/s

Show answer
Correct Option: C

Which is the wrong statement out of the following?

physics reflection of light at curved surfaces uses of curved mirrors uses of spherical mirror uses of spherical mirrors

  1. A concave mirror can give a virtual image.

  2. A convex mirror can give a virtual image.

  3. A concave mirror can give a diminished virtual image.

  4. A convex mirror cannot give a real image.

Show answer
Correct Option: C
Explanation:

The properties of image formed for different object distance are listed below:
Concave mirror:
1)u<f----virtual image , enlarged.
2)f,u,2f---Real, inverted, magnified.
3)u>2f----Real, inverted, diminished.
Convex mirror:
for any object distance virtual,errect and enlarged image.

State whether true or false.
A concave mirror is always used as a street light reflector.

physics reflection of light at curved surfaces uses of curved mirrors uses of spherical mirror uses of spherical mirrors

  1. True

  2. False

Show answer
Correct Option: B
Explanation:

Convex mirrors are used as reflectors in street lights because they are able to spread the light over a wide area.

The temperature in a spherical reflector type solar cooker is raised to more than $500^o C$ by :

physics reflection of light at curved surfaces uses of curved mirrors uses of spherical mirror uses of spherical mirrors

  1. concentrating energy at one point by using a concave reflector

  2. proper insulation of the cooker

  3. concentrating energy at one point by using a covex reflector

  4. both (A) and (B)

Show answer
Correct Option: A
Explanation:

The temperature in a spherical reflector type solar cooler is raided to more than $500^\circ C $ by concentrating energy at one point by using a concave reflector.

Which of the following mirrors is used to concentrate light on a given spot?

physics reflection of light at curved surfaces uses of curved mirrors uses of spherical mirror uses of spherical mirrors

  1. concave mirror

  2. convex mirror

  3. plane mirror

  4. both (B) and (C)

Show answer
Correct Option: A
Explanation:

concave mirror focuses a beam of light from infinity at a point

The mirror used in search lights is.

physics reflection of light at curved surfaces uses of curved mirrors uses of spherical mirror uses of spherical mirrors

  1. concave

  2. convex

  3. plane

  4. convex lens

Show answer
Correct Option: A
Explanation:

The mirror used in search lights is a concave mirror

Concave mirrors are used in :

physics reflection of light at curved surfaces uses of curved mirrors uses of spherical mirror uses of spherical mirrors

  1. reflecting telescopes

  2. magic-lanterns

  3. cinema projectors

  4. all the above

Show answer
Correct Option: D
Explanation:

All the above mentioned optical objects use  concave mirrors.