Question

The rms value of electric field at a distance of 6 m from a 100 W bulb of efficiency 1.2% is:

• A. \(4\;Vm^{-1}\)
• B. \(1\;Vm^{-1}\)
• C. \(2\;Vm^{-1}\)
• D. \(3\;Vm^{-1}\)

Hint:

For electromagnetic waves: \[ I=c\varepsilon_0E_{rms}^2. \] This directly relates intensity and electric field.

Answer 1

The Correct Option is B