JEE Mains · Physics · STD 12 - 8. Electromagnetic waves
The intensity of the light from a bulb incident on a surface is \(0.22 \,W / m ^{2}\). The amplitude of the magnetic field in this light-wave is_______ \(\times 10^{-9} \,T\). (Given : Permittivity of vacuum \(\epsilon_{0}=8.85 \times 10^{-12} \,C ^{2} N ^{-1} m ^{-2}\), speed of light in vacuum \(c =3 \times 10^{8} \,ms ^{-1}\) )
- A \(34\)
- B \(43\)
- C \(40\)
- D \(56\)
Answer & Solution
Correct Answer
(B) \(43\)
Step-by-step Solution
Detailed explanation
\(I =\left(\frac{1}{2} \varepsilon_{0} E _{0}^{2}\right) C\) \(\Rightarrow E _{0} \Rightarrow \sqrt{\frac{2 I }{\varepsilon_{0} C }} \Rightarrow \sqrt{\frac{2 \times 0.22}{8.85 \times 10^{-12} \times 3 \times 10^{8}}}=12.873\)…
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