# Homework Help: Electromagnetic radiation from a lamp

1. Jun 1, 2010

### quantumlolz

1. The problem statement, all variables and given/known data

What is the peak electric field E_0 at 1 m from a 100 W lamp. Assume spherically uniform emission

2. Relevant equations

Magnitude of Poynting vector $$S = \frac{E_0^2}{c\mu_0}$$
And Power = S x Area (2)

3. The attempt at a solution

Sub for S from (1) in (2) and rearranging: $$E_0 = \sqrt{\frac{cP\mu_0}{A}}$$

is A just then $$4\pi d^2$$ where d = 1m?

Then after that just plugging in numbers?