E1 Reflraction on planar mirror
(U17300/U17301)
The law of reflection is demonstrated. When a light
ray impinges a plane mirror under an angle α it is re-
flected under the same angle ß
α = ß
Both angles are measured from the perpendicular line
to the mirror plane.
E2 Reflection on two planar mirrors
(U17301)
An interesting relation can be shown:
δ = 2 γ
where δ is the angle between the incident and the
reflected ray and γ is the angle between the mirrors'
planes.
E3a Reflection of light rays on concave mirror –
rays are parallel to optical axis
(U17300)
The focal length f of the concave mirror is determined
by the length of the line VF. The curvature radius can
be obtained using the known formula:
r
=
f
2
The distance of the centre of curvature S is twice as
long as the distance of the focus F.
E3b Reflection of light rays on concave mirror –
rays are non-parallel to optical axis
(U17300)
The axis ϕ which is perpendicular to the optical axis
and passes through the focus is referred as the focal
plane of the concave mirror. If the parallel rays im-
pinge the mirror, they meet at one point of the axis ϕ
after the reflection. In the case of the rays parallel to
the optical axis, the point belongs to the axis and is
called the focus (F).
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