NEET-XII-Physics
40: Electromagnetic Waves
- #6The sunlight reaching Earth has maximum electric field of 810 Vm-1. What is the maximum magnetic field in this light?Ans : Given:
Electric field amplitude, E0 = 810 V/m
Maximum value of magnetic field = Magnetic field amplitude = B0 = ?
We know:
Speed of a wave =`` \frac{E}{B}``
For electromagnetic waves, speed = speed of light
B0 = µ0 ε0 cE0
Putting the values in the above relation, we get:
`` {B}_{0}=4\,\mathrm{\,\pi \,}\times {10}^{-7}\times 8.85\times {10}^{-12}\times 3\times {10}^{8}\times 810``
`` {B}_{0}=4\times 3.14\times 8.85\times 3\times 81\times {10}^{-10}``
`` {B}_{0}=27010.9\times {10}^{-10}``
`` {B}_{0}=2.7\times {10}^{-6}\,\mathrm{\,T\,}=2.7\,\mathrm{\,\mu T\,}``
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