2. The following are true about the focal lengths of spherical lenses:

a. the first focal length always has the same length as the
second focal length

b. the first focal length of a convex lens is to the right of the lens

c. the first focal length of a concave lens is to the right of the lens

d. the second focal length of a convex lens has a positive sign

e. the second focal length of a concave lens has a negative sign

3. The following are true about magnification by the lens:

a. the linear magnification of an object is defined by the
distance of the image
from the principal plane divided by the distance
of the object from the
principal point.

b. angular magnification is more important than linear magnification
in
determining the image size falling on the retina

c. a tall object situated far away may be perceived as having the same
size as
a smaller one close to the eye

d. magnification of the depth of the image along the optical axis is
known as
axial magnification

e. if the image is situated at infinity, its size is the same as its
object size.

4. The magnifying glass:

a. increases the angle subtended by the image of a near object

b. has an angular magnification which is traditionally defined as angle
subtended by the image divided by the angle subtended
by the same
object placed 25 cm from the eye

c. has an angular magnification equal to M/4 where M is the power of
the lens in dioptres

d. is used to produce erect virtual image for the normal user

e. has a small field of vision

a
a
5. The increasing prismatic effect of the more peripheral parts of
a spherical lens is
responsible for: