NCERT Solutions for Class 7th Science Chapter 11 .5 Reflection of Light — Activity 11.6: Let us experiment
Book page 16011 Updated on2026-09-19
Q1.
Now, place the mirror in the path of the light beam while keeping the comb steady (Fig. 11.9b). What do you observe?
Fig. 11.9(b), page 160 (redrawn sketch): the thin beam from the slit falls on the plane mirror and leaves along a new straight line.
Answer
The thin beam that was running straight along the paper bends away at the mirror and travels off in a new direction. Two straight beams are now seen on the paper — the one going to the mirror and the one coming away from it — meeting at the point where the mirror stands.
The beam from the slit strikes the mirror and leaves it along a new straight path. The reflection happens only at the mirror.
Why it happens: The path of the light beam is changed after falling on the mirror — this is the reflection of light. Notice that the beam is straight before the mirror and straight after it; the mirror only turns it, it does not curve it.
Tip: Keep the comb steady and turn only the mirror. You will see the reflected beam sweep across the paper — the same effect you saw with sunlight on the wall in Activity 11.5.