A plane electromagnetic wave of wave intensity 6 W m- 2 stikes a small mirror of the area 40 cm2, held perpendicular to the approaching wave. The momentum transferred by the wave to the mirror each second will be

Question

A plane electromagnetic wave of wave intensity 6 W m- 2 stikes a small mirror of the area 40 cm2, held perpendicular to the approaching wave. The momentum transferred by the wave to the mirror each second will be (A) 6.4× 10- 7kgms- 1 (B) 4.8× 10- 8kgms- 1 (C) 3.2× 10- 9kgms- 1 (D) 1.6× 10- 10kgms- 1

Tardigrade Admin · Accepted Answer

In the case of complete reflection, the momentum transfer by the wave to the mirror in each second will be P=(2 U/c)=(2 Sa v A/c)=(2 × 6 × 40 × 10- 4/3 × 108) =1.6× 10- 10kgms- 1

Q. A plane electromagnetic wave of wave intensity $6 W m^{- 2}$ stikes a small mirror of the area $40 c m^{2},$ held perpendicular to the approaching wave. The momentum transferred by the wave to the mirror each second will be

$6.4 \times 1 0^{- 7} k g m s^{- 1}$

$4.8 \times 1 0^{- 8} k g m s^{- 1}$

$3.2 \times 1 0^{- 9} k g m s^{- 1}$

$1.6 \times 1 0^{- 10} k g m s^{- 1}$

In the case of complete reflection, the momentum transfer by the wave to the mirror in each second will be
$P = \frac{2 U}{c} = \frac{2 S _{a v} A}{c} = \frac{2 \times 6 \times 40 \times 1 0 ^{- 4}}{3 \times 1 0 ^{8}}$
$= 1.6 \times 1 0^{- 10} k g m s^{- 1}$

Q. A plane electromagnetic wave of wave intensity 6Wm−2 stikes a small mirror of the area 40cm2, held perpendicular to the approaching wave. The momentum transferred by the wave to the mirror each second will be

6.4×10−7kgms−1

4.8×10−8kgms−1

3.2×10−9kgms−1

1.6×10−10kgms−1