What is the electric field amplitude 2m from the source

[kingyof2thejring]

Homework Statement

A 60 W monochromatic point source is radiating equally in all diresctions in a vacum. What is the electric field amplitude 2m from the source.

Homework Equations

Intensity=Power/(4*Pi*r^2), Intensity proportional to square Amplitude

The Attempt at a Solution

I=1.19 Wm-2 what happens next?

 

[Meir Achuz]

Use I=(1/2)\epsilonzero c E^2.

 

[hopeless blonde]

Desperate semi related question. If you have a graph of log intensity against log of (voltage across an LDR in a potential divider circuit)
how do you explain the relationship if your resultant is a straight line of -1.7 obviously in the form of y=mx+c
Log(y)= nlog(x) + logm where y is intensity and x is voltage n being -1.7 and logm being y intercept.
im trying to explain the relationship between the two quantities and ... I am stuck if anyone can help me i would very much appreciate it...

 

[cristo]

Desperate semi related question. If you have a graph of log intensity against log of (voltage across an LDR in a potential divider circuit)
how do you explain the relationship if your resultant is a straight line of -1.7 obviously in the form of y=mx+c
Log(y)= nlog(x) + logm where y is intensity and x is voltage n being -1.7 and logm being y intercept.
im trying to explain the relationship between the two quantities and ... I am stuck if anyone can help me i would very much appreciate it...

Welcome to PF, hopeless blonde. In future, however, please don't hijack another person's thread with your own question-- instead, start a new thread in the relevant homework section.

With regard to your question, you have an equation of the form logy=nlogx+logm. Now, nlogx can be expressed as log(xⁿ). Do you know a rule for loga+logb?