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Light with an energy flux of 25 × 104 Wm–2 falls on a perfectly reflecting surface at normal incidence. If the surface area is 15 cm², the average force exerted on the surface is :
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- 1.25 × 10–6 N
- 2.50 × 10–6 N
- 1.20 × 10–6 N
- 3.0 × 10–6 N
Correct Option: B
Average force
| Fav = | = | |||
| Δt | c |
(∵ Power = F.V)
| = | ||
| 3 × 108 |
2.50 × 10- 6N
