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Physics
Electromagnetic Waves
A plane electromagnetic wave travels in vacuum along z – direction. If the frequency of the wave is 40 MHz then its wavelength is:
5 m
7.5 m
8.5 m
10 m
Wavelength, $\lambda=\frac{c}{v}=\frac{3 × 10^8 ms^{-1}}{40 \times 10^6 s^{-1}}$ = 7.5 m