Question

27. Reflecting surface of the concave mirror is *

1 point

a) Curved inside

b) Curved outside

28. Light ray (Incident ray) which is parallel to the principal axis of a concave mirror after reflection passes through the ______ *

1 point

a) Principal focus /Focus (F)

b) Pole (P)

c) Centre of curvature (C)

29. The diameter of the reflecting surface of spherical mirror is called its aperture. *

1 point

True

False

30. A ray passing through the center of curvature of a concave mirror, after reflection, is reflected back along the same path. *

1 point

True

False

31. The distance between the pole and the principal focus of a spherical mirror is called____ *

1 point

a) Radius of curvature

b) Focal length

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Answer 1

Reflecting surface of the concave mirror is *

a) Curved inside

b) Curved outside

Answer:

Reflecting surface of the concave mirror is (a) Curved inside.

We should remember that Con"cave" in the word itself cave which means Curved inside (polished) and con"vex" which means Curved outside (polished).

28. Light ray (Incident ray) which is parallel to the principal axis of a concave mirror after reflection passes through the ______ 

*a) Principal focus /Focus (F)

b) Pole (P)

c) Centre of curvature (C)

Answer:

Light ray (Incident ray) which is parallel to the principal axis of a concave mirror after reflection passes through the (a) Principal Focus / Focus (F).

Each and every ray which is parallel to (Incident) Principal axis passes through the Focus (F).

Nature of the image formed:

The image formed on the Focus (F) is highly diminished and is point size.

In the vehicles, the bulb is placed at the Focus so, that the image is formed at infinity and the driver could see at a large distance.

29. The diameter of the reflecting surface of spherical mirror is called its aperture.

True

False

Answer:

True

The aperture which is smaller in a spherical mirror then, we use R = 2f

30. A ray passing through the center of curvature of a concave mirror, after reflection, is reflected back along the same path. *

True

False

Answer:

True, A ray passing through the center of curvature of a concave mirror, after reflection, is reflected back along the same path because when we have draw the normal for a ray in spherical mirror we have to draw it from the centre of curvature.

When the ray itself, is passing through the centre of curvature the ray retraces back itself.

31. The distance between the pole and the principal focus of a spherical mirror is called____ *

a) Radius of curvature

b) Focal length

Answer:

The distance between the pole and the principal focus of a spherical mirror is called Focal length.

The principal Focus is exactly half the Length from Pole and the centre of curvature. (R = 2f )