Optics Question 177

Question: In an electromagnetic wave, the amplitude of electric field is 1 V/m. the frequency of wave is 5×1014Hz . The wave is propagating along z-axis. The average energy density of electric field, in Joule/m3, will be

Options:

A) 1.1×1011

B) 2.2×1012

C) 3.3×1013

D) 4.4×1014

Show Answer

Answer:

Correct Answer: B

Solution:

Average energy density of electric field is given by ue=12ε0E2=12ε0(E02)2=14ε0E02

=14×8.85×1012(1)2=2.2×1012J/m3.



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