Question 132: EM waves

Question

Light is incident normally on a completely absorbing surface with an energy flux of 25 W cm
–2
. If the surface
has an area of 25 cm
2
, the momentum transferred to the surface in 40 min time duration will be :

Accepted Answer

$$P = {{\Delta E} \over C}$$
$$ = {{\left( {25 	imes 25} ight) 	imes 40 	imes 60} \over {3 	imes {{10}^8}}}N - s$$
$$ = 5 	imes {10^{ - 2}}N - s$$

Answer

6.3 × 10
–4
Ns

Answer

5.0 × 10
–3
Ns

Answer

1.4 × 10
–6
Ns

Answer

3.5 × 10
–6
Ns

EM waves

Light is incident normally on a completely absorbing surface with an energy flux of 25 W cm –2 . If the surface has an area of 25 cm 2 , the momentum transferred to the surface in 40 min time duration will be :

Choose the correct answer: