General science

1. What is difference between mass of body and its weight?
- Mass is a measure of the quantity  of matter whereas weight is a force.

2. Why speed of sound is greater in solids than in liquids?
- Because the solids have high  elasticity.
3.How many images will be formed when an object is placed between two mirrors placed parellel to each other?
- Infinite
4.At which point of earth  weight of object will be minimum?
- At the center of earth
5.When an open bottle of scent is kept at one corner due to which phenomenon its fragrance is found in whole room?
- Diffusion
6.What happens to speed of sound with rise in temperature?
- Increases
7.If in a mirror image of object appears to be larger then which type of mirror is used?
- Concave mirror
8.Why bubble of water shines?
- Due to phenomenon of total internal reflection.
9.An air bubble in water acts as which lens?
- Concave lens
10.Why clear nights are more colder then cloudy nights?
- Due to radiation
11.Why sky appears to be blue?
- Because blue colour of light is of shorter wavelength so easily scattered by dust particles and water vapour.
12.How water in earthen pots remain cool?
- Because water keeps on passing out from pores and evaporating.