Question

1. Which property of concave mirror is utilized for using them as shaving mirrors?
2. Light passes through a rectangular glass slab and through a triangular glass prism. Using proper ray diagram, explain in what way does the direction of the two emergent beams differs with respect to the incident beam of light
3. A concave lens has a focal length of 50 cm. Calculate its power.

Answer 1

1. Concave mirrors are used as magnifying mirrors for shaving. So, the object is placed between principal focus and the pole for the same.
2. In rectangular glass slab, the emergent ray is parallel to the original path of the incident ray while in the triangular glass prism, the emergent ray is not parallel to the incident ray. In fact, it bends towards the thicker part i.e., the base of the prism.

3. f = - 50 cm = -(50/100) m = -1/2 m
Power = -2D