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Question
In torches, search lights and headlights of vehicles the bulb is placed ______.
Options
between the pole and the focus of the reflector
very near to the focus of the reflector
between the focus and centre of curvature of the reflector
at the centre of curvature of the reflector
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Solution
In torches, search lights and headlights of vehicles the bulb is placed very near to the focus of the reflector.
Explanation -
In torches, search lights and headlights of vehicles concave mirrors are used. When a light source is placed at the focus of the mirror, after reflection light rays become parallel to the principal axis. Due to this, the bulb is placed very near to the focus of the reflector.
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