Tag: uses of curved mirrors

Questions Related to uses of curved mirrors

_________ mirrors are used in telescopes.

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. No

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Correct Option: A
Explanation:

Concave mirrors provide large images and the purpose of telescope is to view long distance images.

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?

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

  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

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Correct Option: B
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.

State whether true or false : 

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

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

  1. True

  2. False

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Correct Option: A
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.

The mirror used by E.N.T. specialists is _____

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

  1. Plane

  2. Concave

  3. Convex

  4. None of these

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Correct Option: B
Explanation:

The mirror used by E.N.T. specialists is concave mirror. 

Concave mirror concentrate all the rays at desired part which makes it bright.

In torches, search lights and headlights of vehicles the bulb is placed:

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

  1. between the pole and the focus of the reflector

  2. very near to the focus of the reflector

  3. between the focus and centre of curvature of the reflector

  4. at the centre of curvature of the reflector

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Correct Option: B
Explanation:

In torches, search lights and headlights of vehicles the bulb is placed very near to the focus of the reflector to get a parallel beam of light through which we can see to a longer distance.

Magnification produced by a rear view mirror fitted in vehicles:

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

  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

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Correct Option: A
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.

The 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 telescope

  2. Magic-lanterns

  3. Cinema projectors

  4. All of these

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Correct Option: D
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.

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

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

  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

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Correct Option: B,C
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.

___________ are used in telescopes to reflect light.

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

  1. Concave mirrors

  2. Convex mirrors

  3. Plane mirrors

  4. Convex lenses

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Correct Option: A
Explanation:

Concave mirrors are used in telescope to reflect light.


Answer-(A).

The light emanating from a torchlight is

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

  1. Convergent

  2. Divergent

  3. Parallel

  4. Irregular

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Correct Option: B
Explanation:

A torch has a bulb working on a battery. A bulb spreads its light rays in all directions. Thus it always diverges.