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If the electric field associated with a ...

If the electric field associated with a radiation of frequency 10 MHz is `E=10 sin (kx - omega t)` mV/m then its energy density is …. `J m^(-3)`. [epsilon_(0) = 8.85xx10^(-12)C^(2)N^(-1)m^(-2)]`

A

`4.425xx10^(-16)`

B

`6.26xx10^(-14)`

C

`8.85xx10^(-16)`

D

`8.85xx10^(-14)`

Text Solution

Verified by Experts

The correct Answer is:
A
`E_(rms)^(2)=(E_(m))/(sqrt(L))`
`therefore E_(rms)^(2)=(E_(m)^(2))/(2)`
`rho=epsilon_(0)E_(rms)^(2)`
`therefore rho =(8.85xx10^(-12)xx100xx10^(-6))/(2)`
`=4.425xx10^(-16)`
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Knowledge Check

  • Intensity of electromagnetic wave is 0.02 "wattmeter"^(-2) and its velocity in space is 3xx10^(8)ms^(-1) then energy density of radiation is ….. Jm^(-2)

    A
    `6.67xx10^(11)`
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  • To get 2F capacitance, the area of each plate kept at separation of 2 mm is ...... . ' ( epsilon_(0) = 8.85 xx 10^(-12) MKS)

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    B
    `4.51 xx10^(5) m^(2)`
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