Question

According to the new Cartesian sign convention for lenses, heights measured below the principal axis are taken as:

Options

• Zero

• Equal to the object height

• Positive

• Negative

Answer 1

In the new Cartesian sign convention, heights measured above the principal axis are taken as positive, while heights measured below the principal axis are taken as negative. This is why inverted real images formed by convex lenses have negative image heights.