Physics

Light and Mirrors

454 Questions

Light and mirrors questions cover the principles of reflection, image formation, and mirror magnification. Concepts include the properties of plane mirrors, the uses of concave mirrors in solar devices, and the behavior of light rays. These fundamentals are essential general science topics in major competitive examinations.

Plane mirror propertiesConcave mirror applicationsMirror magnification formulaLight reflection lawsImage formation

Light and Mirrors Questions

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

Mirrors on the outside of the passenger side of the cars often contain a message that says something like. "Objects are closer than they appear." In the other words, the images seen in the mirror, although looking like the objects in other respects, appear to be further away than they actually are, because the images are the smaller than the objects.
What kind of mirror is being used in this case? 

  1. plane mirror

  2. convex mirror

  3. concave mirror

  4. The mirror could be concave or convex.

  5. The mirror could be flat or concave.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Convex mirrors are used in this case.

Since the mirrors are bend outwards, a large range in area to view is covered to see objects behind in cars.
The magnification of the objects is lesser than one for distant objects for convex mirrors. Hence the objects appear farther away than they actually are.

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

Mirrors on the outside of the passenger side of cars often contain a message that says something like, "Objects are closer than they appear." In other words, the image seen in the mirror, although looking like the objects in other respects, appear to be further away than they actually are, because the images are smaller than the objects.
What kind of mirror is being used in this case?

  1. Plane mirror

  2. Convex mirror

  3. Concave mirror

  4. The mirror could be concave or convex

  5. The mirror could be flat or concave
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The mirror used is a convex mirror. 
Since it forms virtual and 'diminished' images, the objects appear to be distant in the mirror than they actually are.

Also the outward curvature of the mirror makes it cover more area to view.

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

State whether true or false : 

Convex mirrors enable the driver to view much larger area than would be possible with a plane mirror.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Convex mirror give an erect ,virtual,full size image of distant object with a wider field of view. Thus,convex mirrors enables the driver to view much larger area than would be possible with a plane mirror.

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

Magnification produced by a rear view mirror fitted in vehicles:

  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
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

We know, magnification(M)$=\dfrac{\text {height  of  image}\ (h _i)}{\text{height  of  object}\ (h _o)}$
If the magnification will be 1 or more than 1, then the height of image will be equal or greater than the height of object. So, only a part of the image will be viewed through the possible aperture of the mirror. This situation will not provide the driver with the detailed idea of motion of vehicles following.
Hence, Magnification produced by a rear view mirror fitted in vehicles is less than one.

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

The concave mirrors are used in:

  1. Reflecting telescope

  2. Magic-lanterns

  3. Cinema projectors

  4. All of these
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

A reflecting telescope uses concave mirrors as they produce images similar to the images produced by convex lenses i.e. upright and smaller than the object.

The magic lantern used a concave mirror in back of a light source to direct as much of the light as possible through a small rectangular sheet of glass.

Concave mirrors project a beam of light outward, which is required in a cinema projector.

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

A concave mirror forms an image of the sun at a distance of 12 cm from it. Then:

  1. the radius of curvature of this mirror is 6 cm

  2. to use it as a shaving mirror, it can be held at a distance of 8-10 cm from the face

  3. if an object is kept at a distance of 24 cm from it, the image formed will be of the same size as the object

  4. all the above alternatives are correct
Reveal answer Fill a bubble to check yourself
B,C Correct answer
Explanation

Concave mirror forms an image of the sun at a distance of 12 cm.
So the focal length of mirror is 12 cm.
Radius of mirror is $f \times 2=24cm$
For shaving we need to get a virtual image which should be magnified and erect.
So the mirror must be kept at a reasonable distance of 8-10 cm which is within focus and pole.
As the radius is 24cm the object placed at center forms image at the same place
Options $B,C$ are correct.