Question

An electromagnetic wave strikes a 2.00-cm2 section of wall perpendicularly. The rms value of the wave's magnetic field is determined to be 5.00 10-4 T. How long does it take for the wave to deliver 1600 J of energy to the wall?

Answer 1

Answer:t=0.134 s

Step-by-step explanation:

Given

Area of wall over which wave strikes
`A=2\ cm^2`

Intensity of Electromagnet wave is
`I=(c)/(\mu _o)B_(rms)^2`

where [/tex]c[/tex]=speed of light

`\mu _o`=Permeability of free space

`B_(rms)`=RMS value of magnetic field

`I=(3* 10^8)/(4\pi * 10^(-7))* (5* 10^(-4))^2`

`I=5.96* 10^7\ W/m^2-s`

Average power is

`P=I\cdot A`

`P=5.96* 10^7* 2* 10^(-4)`

`P=11.92* 10^(3)`

`P=11.92\ kW`

time taken
`t=(Energy)/(Power)`

`t=(1600)/(11.92* 10^3)`

`t=0.134\ s`