Suppose that the electromagnetic wave in vacuum is →E={(3.1NC)cos[(1.8radm)y+(5.4×106rads)t]^i What is the frequency?
A
8.6×105Hz
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B
4.3×105Hz
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C
8.6×103Hz
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D
4.3×103Hz
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Solution
The correct option is A8.6×105Hz Comparing the given equation with general form of wave equation E=E0cos(ky−ωt) we get ω=5.4×106rad/s We know that frequency is given by ν=ω2π Putting value of ω and solving we get ν=8.6×105Hz