In Fig. (a), the shape of the shadow is _____.

Choose the correct option from the following:
(opaque, luminous, transparent, non-luminous)
A piece of glass is _____ material.

Choose the correct option from the following:
(size, colour, weight, dark outline)
A shadow only shows the _____ of the object.

Classify the following materials into transparent, translucent and opaque materials:
cloth, tracing paper, glass sheet, wooden sheet and tissue paper.