3B Scientific U14600 Optics on magnetic boards - Manual (Page 6)

Exp.19: Virtual image formed by a
concave lens
Two pencils of light, one parallel to the
optical axis and the other through the
optical centre, intersect in the object
point. The refracted ray due to the parallel
ray is extended until it intersects the ray
passing through the centre. The virtual
image is smaller than the object
Exp.20: Cancelling out of the
refraction
When light rays pass through an object
made up of a concave and a convex lens
with the same curvature the refraction is
cancelled out.
Exp.20: Shadow casting
Light rays from the reverse side of the
multiple-ray projector are used for
experiments on shadow-casting.
Exp.21: Eclipse of the sun
The two round shadow-casting bodies are
placed on the board to represent the
moon and the earth. When the moon’s
shadow strikes the earth a solar eclipse
can be observed, partial in the penumbral
and total in the umbral shadow..
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