Geometric Optics

  • Prelab 1:

Rearrange

,

as

,

where

.

We can plot and LINEST sinθ1 vs sinθ2, say the slope is m, then

.

    • You can also plot and LINEST n1sinθ1 vs sinθ2, and the refractive index, n2 is just the slope.
  • Prelab 2:

Given

,

which can be rearranged as

.

We can plot and LINEST 1/S0 vs 1/Si, say the y-intercept is b, then

.

  • 1. Measuring the refractive index of the block:

The uncertainty of sinθ is cosθδθ, and δθ should be expressed in radian, not degree.

  • 2. Measuring the focal lengths of two lenses:

The uncertainty should be calculated from prelab 2.

Using error propagation, the uncertainty of y (i.e., 1/So) and x (i.e., -1/Si) should be

.

  • 3. Building a telescope:

The distance between the two lenses should be equal to the sum of their focal lengths.

The theoretical magnification factor of the telescope is then,

,

with

.

and the measured magnification factor can be determined from measuring the height of an object with and without the telescope:

Fig 1. Magnification Measurement. (Image Credit: Nate Welsh)