Index of refraction in an air bubble

[tiger1]

[SOLVED] Index of refraction

Homework Statement

An air bubble inside an 9.00 cm-diameter plastic ball is 2.90 cm from the surface.

As you look at the ball with the bubble turned toward you, how far beneath the surface does the bubble appear to be?

Homework Equations

n_1/s + n_2/s' = n_2-n_1/R

The Attempt at a Solution

1.59/.0290 + 1/s' = 1-1.5/.045
s'=1.52

I'm not sure why that isn't correct.

...

1.59/.0290+1/s' = 1.59-1/.045
s'=.024m <- correct

 

[rl.bhat]

Here s' is virtual. So it should be -ve.
Your value is correct.