In the same way make a big concave mirror to heat up a vessel.
You might have observed the TV dish antenna. Make a wooden/ iron
frame in the shape of TV dish. Cut acrylic mirror sheets in
to 8 or 12 pieces in the shape of isosceles triangles with a
height equal to the radius of your dish antenna. The bases of
8 or 12 triangles together make the circumference of the
dish. Stick the triangle mirrors to the dish as shown in figure-
24.
Your solar heater/cooker is ready.
Arrange it so that concave part faces sun. Find its focal
point and place a vessel at that point. The vessel gets heated
enough to cook rice.
In practical applications (like in car-headlights), concave
mirrors are of parabolic shape (see figure 25)
• Normal to the curved surface at a point on it is the line joining the centre of curvature and
that point.
Your solar heater/cooker is ready.
