- 128

- 0

_{0}√(ε/μ)

so

E

_{0}= √2*N*(ε/μ)

where the value of ε/μ is 376.7Ω

I have a similar question to this, below, regarding amplitude of an oscillating magnetic field.

Yes, I'd like the answer, but am initially stuck deciding whether the mW is milli- or mega-

**2. Homework Equations**

A laser found in supermarket checkout scanners emits light in a 1.1 mm diameter beam with a power of 1.3 mW.

Part A

What is the amplitude of the oscillating electric field in the laser beam?

Express your answer to two significant figures and include the appropriate units.

=

Part B

What is the amplitude of the oscillating magnetic field in the laser beam?

Express your answer to two significant figures and include the appropriate units

**Part A**

N = 1/2 E

_{0}√(ε/μ)

so

E

_{0}= √2*N*(ε/μ)

where the value of ε/μ is 376.7Ω

E

_{0}= √2*10

^{3}*376.7Ω

= 877.0 V m

^{-2}

Not sure how to find the amplitude of the oscillating magnetic field though.

Any help gratefully received.