A plane electromagnetic wave is incident on a plane surface of area A, normally and is perfectly reflected. If energy E strikes the surface in time t then average pressure exerted on the surface is ( c= speed of light)

Question

A plane electromagnetic wave is incident on a plane surface of area A, normally and is perfectly reflected. If energy E strikes the surface in time t then average pressure exerted on the surface is ( c= speed of light) (A) zero (B) E/Atc (C) 2E/Atc (D) E / C

Tardigrade Admin · Accepted Answer

Incident momentum, p=(E/c) For perfectly reflecting surface with normal incidence Δ p=2 p=(2 E/c) F=(Δ p/Δ t)=(2 E/c t) P=(F/A)=(2 E/c t A)

Q. A plane electromagnetic wave is incident on a plane surface of area $A$ , normally and is perfectly reflected. If energy $E$ strikes the surface in time $t$ then average pressure exerted on the surface is ( $c =$ speed of light)

zero

$E / A t c$

$2 E / A t c$

$E / C$

Incident momentum, $p = \frac{E}{c}$
For perfectly reflecting surface with normal incidence
$Δ p = 2 p = \frac{2 E}{c}$
$F = \frac{Δ p}{Δ t} = \frac{2 E}{c t}$
$P = \frac{F}{A} = \frac{2 E}{c t A}$

Q. A plane electromagnetic wave is incident on a plane surface of area A, normally and is perfectly reflected. If energy E strikes the surface in time t then average pressure exerted on the surface is ( c= speed of light)

zero

E/Atc

2E/Atc

E/C

Incident momentum, p=cE​ For perfectly reflecting surface with normal incidence Δp=2p=c2E​ F=ΔtΔp​=ct2E​ P=AF​=ctA2E​

Q. A plane electromagnetic wave is incident on a plane surface of area $A$ , normally and is perfectly reflected. If energy $E$ strikes the surface in time $t$ then average pressure exerted on the surface is ( $c =$ speed of light)

$E / A t c$

$2 E / A t c$

$E / C$

Incident momentum, $p = \frac{E}{c}$
For perfectly reflecting surface with normal incidence
$Δ p = 2 p = \frac{2 E}{c}$
$F = \frac{Δ p}{Δ t} = \frac{2 E}{c t}$
$P = \frac{F}{A} = \frac{2 E}{c t A}$