Tag: image formation by plane mirror

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Questions Related to image formation by plane mirror

Multiple choice evs magic with mirrors introduction to light and mirror image formation by plane mirror light : reflection and refraction from plane surface

A real image of a distant object is formed by a plano-convex lens on its principal axis. Spherical aberration

  1. is absent

  2. is smaller if the curved surface of the lens faces the object

  3. is smaller if the place surface of the lens faces the object

  4. is the same whichever side of the lens faces the object
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

For a plano-convex lens, spherical aberration is minimized when the curved surface faces the side with the smaller conjugate distance (the side with the more divergent rays). For a distant object, this means the curved surface should face the object.

Multiple choice evs magic with mirrors introduction to light and mirror image formation by plane mirror light : reflection and refraction from plane surface

In case of reflection by a plane mirror, which of the following statement are not correct?

  1. It can never give real image

  2. It can never give inverted image

  3. It changes left into right

  4. It changes front into back
Reveal answer Fill a bubble to check yourself
A,B,D Correct answer
Explanation

In case of reflection an by a plane mirror, it does not give a real, inverted image and image never changes front into back.

Multiple choice evs magic with mirrors introduction to light and mirror image formation by plane mirror light : reflection and refraction from plane surface

An object is placed symmetrically between the two plane mirrors inclined at angle of $30^o$. Then the total number of images formed is:

  1. 12

  2. 2

  3. 11

  4. 15
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

No. of image $ = \dfrac{ 360^{\circ}}{ \theta} – 1$

                                             $ = 12-1$
                                             $ = 11$

Multiple choice evs magic with mirrors introduction to light and mirror image formation by plane mirror light : reflection and refraction from plane surface

It is necessary to illuminate the bottom of a well by reflected solar beam when the light is incident at an angle of $\alpha = {40}^{\circ}$ to the vertical. At what angle $\beta$ to the horizontal should a plane mirror be placed?

  1. ${70}^{\circ}$
  2. ${20}^{\circ}$
  3. ${50}^{\circ}$
  4. ${40}^{\circ}$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The light is incident at 40 degrees to the vertical, so it makes an angle of 50 degrees with the horizontal. To reflect this light vertically downward, the mirror must bisect the angle between the incident ray and the vertical. The angle of the mirror to the horizontal is 70 degrees.

Multiple choice physics light : reflection and refraction from plane surface introduction to light and mirror magic with mirrors image formation by plane mirror principle of reversibility of path of light refractive index

A plane mirror is in a vertical plane and is rotating about a vertical axis at 100 mm horizontal beam of light is incident on the mirror. The reflected beam will rotate at

  1. $100 rpm$
  2. $141 rpm$
  3. $0 rpm$
  4. $200 rpm$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

When a mirror rotates at an angular velocity omega, the reflected ray rotates at an angular velocity of 2*omega. Therefore, if the mirror rotates at 100 rpm, the reflected beam rotates at 200 rpm.

Multiple choice physics light : reflection and refraction from plane surface introduction to light and mirror magic with mirrors image formation by plane mirror principle of reversibility of path of light refractive index

When a mirror is rotated through an angle, the reflected ray moves through double that angle, the instrument based on the above principle is :

  1. Periscope

  2. Odometer

  3. Refractometer

  4. Sextant
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

A periscope is based on the principle of reflection.

An Odometer is used to measure the distance travelled by a vehicle.
A Refractometer is based on the principle of refraction (Snell'slaw).
A Sextant is used to measure the angle between two visible objects. Baesd on the principle that when a mirror is rotated through an angle the reflected ray moves through double of that angle.

Multiple choice physics light : reflection and refraction from plane surface introduction to light and mirror magic with mirrors image formation by plane mirror principle of reversibility of path of light refractive index

A source of light lies on the angle bisector of two plane mirrors inclined at an angle $\theta$. The values of $\theta$, so that the light reflected from one mirror does not reach the other mirror will be

  1. $\theta \geq 120^0$
  2. $\theta \geq 90^0$
  3. $\theta \leq 120^0$
  4. $\theta < 30^0$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

For the light reflected from one mirror not to reach the other, the angle of incidence on the second mirror must be such that it cannot be reflected. This occurs when the angle between the mirrors is 120 degrees or more.

Multiple choice physics light : reflection and refraction from plane surface introduction to light and mirror magic with mirrors image formation by plane mirror principle of reversibility of path of light refractive index

In a Michelson experiment for measuring speed of light, the distance traveled by light between two reflections from the rotating mirror is 4.8 km. The rotating mirror has a shape of a regular octagon. At what minimum angular speed of the mirror (other than zero) the image is formed at the position where a non-rotating mirror forms it?

  1. $780$ $rev/s$
  2. $7800$ $rev/s$
  3. $690$ $rev/s$
  4. $7500$ $rev/s$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Minimum angular speed $ f=\dfrac { c }{ dN }$


$ =\dfrac { 3\times { 10 }^{ 8 } }{ 4.8\times { 10 }^{ 3 }\times 8 }$

$ =7812rev/s\cong 7800rev/s$

Multiple choice physics light : reflection and refraction from plane surface introduction to light and mirror magic with mirrors image formation by plane mirror principle of reversibility of path of light refractive index

A plane mirror which rotates $10^4$ times per minute reflects light on to a stationary mirror $50$ m away. This mirror reflects the light normally so that it strikes the rotating mirror again. The image observed in the rotating mirror is shifted through $2.4$ minutes from the position it occupies. When the rotating mirror is stationary, what is the speed of light?

  1. $3\times 10^8$ m/s
  2. $4\times 10^8$ m/s
  3. $5\times 10^8$ m/s
  4. $6\times 10^8$ m/s
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

This is a classic Fizeau or Michelson-type experiment setup. Using the formula for the speed of light c = 4*N*D*theta, where N is frequency, D is distance, and theta is the deflection angle, the calculation yields 3*10^8 m/s.