12. Light and sound
12. Light and sound Fill in the blanks. 1. Objects which cannot give out their own light are called Non - luminous. 2. Trandparent object allow light to pass through them completely. 3. Reflection is bouncing back of light from a smooth shiny surface. Write true or false. 1. Sound does not require any medium to travel. (F) 2.The sound of loudspeaker is an unpleasant sound. (T) 3.sound travels through air in the form of particles. (F) Let us practise 1. Fill in the blanks. a. Noise is produced by irregular sound waves. b. Sun is the main source of heat and light on earth. c. When light hits a surface and cannot pass through it, the surface is called opaque. d. Sound is produced due to vibration of objects. 2 . Write 'T' for true and 'F' for false. a. Honking car is an example of a pleasant sound. (F) b. Light cannot bend around the cornera. (T) c. Wat...