Description : Consist of a steel disc diameter 500 mm in matt white color,
marked at every 5 with bigger lines at 10 and 30 and with
cross cutting lines at 90 for taking centre. Disc mounted on a
steel tube diameter 25 mm length 400 mm on a heavy stable
cast tripod base. Disc freely rotatable at centre can be
stopped at any position by friction disc. Lamp house in two
parts, the outer rotatable and slotted gives light beams of
varying width, narrow single, double and triple beams. Inner
having the lamp holder and a 12 V 24 W s.b.c. axial filament
lamp. Attached to the lamp house is adjustable lens carrier
with lens to give diverging, parallel or converging light
beams, lamphouse mounted on a rotatable arm can be
stopped at any position by friction disc.
Accessories :-I.
For Reflection
(a) A plane glass mirror size 50 x 25 mm, mounted
in a wooden holder and with a magnet for
attachment to the disc.
(b) A polished plated metal cylindrical mirror of radius 75
mm with two magnets.
II. For Refraction
