Mirror Formula Sums

What is the relationship between the radius of curvature of the mirror, and it's focal length?

• They are equal in magnitude but opposite in sign.
• They are equal in both magnitude and sign.

• The radius of curvature is double the focal length.

• Focal length is double of the radius of curvature.

Which options are true for sign conventions used for spherical mirrors?

• Distances in front of the mirror are negative and distances behind the mirror are positive.
• Lengths above the principal axis are negative, and lengths below the principal axis are positive.

• Lengths above the principal axis are positive, and lengths below the principal axis are negative.

• Distances in front of the mirror are positive and distances behind the mirror are negative.

An object of height 5 cm forms a real image of height 2 cm in a spherical mirror. What is the magnification?

• • -0.4

• 0.2
• 0.4

• -3.5

The magnification produced by a mirror is -1.5. What does it signify about the image formed? Which type of mirror can produce this image?

• Real, upright, and diminished; Concave mirror

• Virtual, inverted, and magnified; Plane mirror

• Virtual, upright, and diminished; Convex mirror

• Real, inverted, and magnified; Concave mirror

An object 3 cm high is placed at a distance of 10 cm in front of a concave mirror of focal length 20 cm. What is the position, nature and size of the image formed?

• The image is formed at 20 cm in front of the mirror, real, inverted, and diminished, of size 1 cm.

• The image is formed at 40 cm in front of the mirror, virtual, upright, and magnified, of size 10 cm.

• The image is formed at 20 cm behind the mirror, virtual, upright, and magnified, of size 6 cm.

• The image is formed at 30 cm in front of the mirror, real, inverted, and the same size as the object.

A convex mirror has a focal length of 10 cm. Where should the object be placed to get an image that is half the size of the object?

• 5 cm in front of the convex mirror.

• 10 cm in front of the convex mirror.

• 25 cm in front of the convex mirror.

• 15 cm in front of the convex mirror.

A concave mirror produces a three times upright and enlarged image of an object placed at 10 cm in front of it. What is the radius of curvature of the mirror?

• 20 cm
• 40 cm

• 30 cm

• 15 cm