# Error estimation

1. Oct 9, 2009

### Mechdude

1. The problem statement, all variables and given/known data
i did a lab on determination of refractive index of an opaque dielectric material, using the brewster angle. We took a couple of readings on a spectrometer at the position of complete extinction,
now how do i get the error estimate ? The angles were taken to the nearest minute

2. Relevant equations

$$tan \theta_B = \frac {n_t}{n_i}$$

3. The attempt at a solution

2. Oct 11, 2009

### lanedance

you could look at dreivatives

you have the refractive index calculated in terms of the angle
$$n = f(\theta)$$

for a small change in angle
$$d \theta$$

what is the corresponding change in refractive index?
$$dn = \frac{df(\theta)}{d\theta}d\theta$$