# Homework Help: Log + Ritcher Scale

1. Dec 11, 2007

### Macleef

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

See image

2. Relevant equations

M = log(I_i / I_o)

3. The attempt at a solution

See image

2. Dec 11, 2007

### wildman

No, no... you are making it far too complicated.

What is $$I_X$$ in terms of $$I_E$$ ? In other words, what number do you have to multiply $$I_E$$ by to get $$I_X$$?
Then get rid of $$I_X$$ in your equation.
Finally think about what multiplication inside of a log function maps to on the outside. I'll give you a clue on the last one and it is +.

Last edited: Dec 11, 2007