Define 1. Shadow 2.luminious Object 3. …

•    An object which gives out its own light is called a luminous object.
•    When an object is placed in front of a source of light, it produces a shade behind it, called shadow.
•    Those materials which allow electric current to pass through them are called conductors.
•    Those materials which do not allow electric current to pass through them are called insulators.
•    The changing of water into water vapour is called evaporation.
•    The loss of water from plants as water vapour through the pores of their leaves is called transpiration.
•    The changing of water vapour into liquid water on cooling is called condensation.
•    The activity of collecting rainwater directly and store it in big tanks for later use, or making the rainwater percolate into ground more efficiently to recharge the ground water, is called rainwater harvesting.