JEE PYQ: Electromagnetic Waves Question 9
Question 9 - 2021 (25 Feb 2021 Shift 2)
The peak electric field produced by the radiation coming from the 8 W bulb at a distance of 10 m is $\frac{x}{10}\sqrt{\frac{\mu_0 c}{\pi}}$. The efficiency of the bulb is 10% and it is a point source. The value of $x$ is ______.
Show Answer
Answer: 2
Solution
Using $I = \frac{1}{2} c \epsilon_0 E_0^2 = \frac{P_{\text{eff}}}{4\pi r^2}$ with effective power $= 0.8$ W gives $x = 2$.
BETA
