Question

In case of a concave mirror, a ray parallel to the principal axis after reflection will

• A. Pass through the principal focus
• B. Diverge from the principal focus
• C. Reflect back to the object
• D. Pass through the centre of curvature

Hint:

For a concave mirror: Parallel ray \(\to\) Passes through Focus (\(F\)).
For a convex mirror: Parallel ray \(\to\) Appears to diverge from Focus (\(F\)).
This is the basic foundation for drawing ray diagrams.

Answer 1

The Correct Option is A

Step 1: Recall the definition of principal focus.
The principal focus of a concave mirror is defined precisely as the point where rays travelling parallel to the principal axis meet after reflecting.
Step 2: Trace a parallel ray.
A ray coming in parallel to the axis strikes the curved concave surface and is turned inward by reflection, heading back across the axis rather than staying parallel.
Step 3: Follow it to where it lands.
Because the mirror is concave, this reflected ray converges with all other such rays at that one defined focus point on the axis.
\[ \boxed{\text{Passes through the principal focus}} \]