Electromagnetic Waves

JEE Main level, single correct, medium

108 of 165

Question 108 of 165

The mean intensity of radiation on the surface of the Sun is about 108W/m2.{10}^{8}W/{m}^{2}. The rms value of the corresponding magnetic field is closest to:

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Answer: (D) 10−4T{10}^{-4}T

I=B022μ0×CI=\dfrac{{B}_{0}^{2}}{2{\mu }_{0}}\times C

B0=2μ0IC{B}_{0}=\sqrt{\dfrac{2{\mu }_{0}I}{C}}

Brms=μ0IC=4π×10−7×1083×108{B}_{rms}=\sqrt{\dfrac{{\mu }_{0}I}{C}}=\sqrt{\dfrac{4\pi \times {10}^{-7}\times {10}^{8}}{3\times {10}^{8}}}

≈10−4T\approx {10}^{-4}T

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