3B Scientific U14600 Optics on magnetic boards User Manual

Page 3

Exp.7: Refraction from a less dense to
a more dense medium
A pencil of light is projected at the upper
surface of the plane-parallel plate. The
normal and the extension of the refracted
ray are drawn on the white board. The
phenomenon of refraction is clearly
visible. If light passes from a less dense
to a more dense medium the refraction
angle β is smaller than the incidence
angle α.

Exp.8: Refraction from a more dense
to a less dense medium
The plane mirror is set behind the plane-
parallel plate. It produces a return pencil
of light which demonstrates the deviation
away from the normal when the ray
passes from the more dense to the less
dense medium. Incident angle α and
emergent angle β are equal.

Exp.9: Parallel displacement by a
plane-parallel plate
If a light ray passes through a plane-
parallel plate its direction is not changed.
The shift v of the outgoing ray can be
determined by using the formula:
v = d*sin(α-β)/cosβ

Exp.10: Semi-circular body

_

Light

incident at the center
If a light ray passes through the centre of
curvature of a semi-circular body it will
emerge perpendicular to the tangent at
the point of emergence and will undergo
no second deviation.