What Produces What?
Only concave mirrors can
produce real images
(if s 0 ≻ f). Convex mirrors
and plane mirrors can only
produce virtual images.- Show why convex mirrors can only form virtual images.
Here’s How to Crack It
Because f is negative and so is positive, the mirror equation
immediately tells us that si cannot be positive (if it were, the left-hand side would
be the sum of two positive numbers, while the right-hand side would be negative).
Since si must be negative, the image must be virtual.
Questions 21-23An object placed 60 cm in front of a spherical mirror forms a real
image at a distance of 30 cm from the mirror.- Is the mirror concave or convex?
- What’s the mirror’s focal length?
- Is the image taller or shorter than the object?
Here’s How to Crack It
- The fact that the image is real tells us that the mirror cannot be convex,