The distance from the center of mirror curvature and its focus equals

• diameter of curvature.

• quarter of the diameter of curvature.

• half of the focal length.

A concave mirror of focal length 5 cm, its diameter of curvature equals ---------

• 5

• 10

• 15

• 20

A concave mirror was cut from hollow spherical glass ball of diameter 16 cm its focal length is --------

• 4

• 8

• 16

A spherical mirror whose radius is 60 cm, its focal length is equal to -------------

• 15

• 30

• 7.5

A concave mirror has a focal vertex (length) of 10 cm, the radius of curvature of its ----------------------------

• 10

• 5

• 20

A concave mirror with a focal length of 20 cm, and the object is placed at a of 50 cm from the mirror, the image is formed at a distance -------------------

• more than 40 cm.

• equals 20 cm.

• more than 20 cm, and less than 40 cm.

An object when it is placed at a distance less than the focal length of the convex lens, the properties of the image formed are ---------------

• real, invented and enlarged.

• virtual, upright and enlarged.

• real, inverted and smaller.

An object is placed at the focus of a convex lens, the image will be -------------------

• between the focus and the center of curvature.

• not formed

• no correct answer.

If an object is put at a distance greater than the double of focal length of a convex lens the image is formed --------

• at the double of focal length.

• between the focus and the center of curvature

• at infinity

On putting a torch in front of a convex lens at a distance equals its focal length, the light rays emerged from the lens are...

• parallel

• diverged.

• converged.