Question

According to the New Cartesian Sign Convention for mirrors, what sign has been given to the following:

a. Height of inverted and real image.

b. Focal length of a convex mirror.

Answer 1

The explanation for part a

1. The distance measured below the principal axis is taken as negative.
2. Inverted images form below the principal axis.
3. Hence, the height of the inverted and real image is negative.

The explanation for part b

1. The focal length of the convex mirror is positive.
2. The focal length of a convex mirror is positive because it is measured on the right side of the pole of the mirror that is along the positive x-axis.