question_answer 43)

  In torches, search lights and headlights of vehicles, the bulb is placed (a) between the pole and the focus of the reflector (b) very near to the focus of the reflector (c) between the focus and centre of curvature of the reflector (d) at the centre of curvature of the reflector

Answer:

                  (B) Concave mirrors are commonly used in torches , search lights and vehicles headlights to get powerful parallel beams of light. Here the bulb is placed very near to the focus of the reflector as the incident rays, which passes-through the focus of concave mirror, after reflection become parallel to the principal axis of the mirror.