When an open bottle of scent is kept in a corner of the room, its odor is felt in all the corners. This is due to the phenomenon of _____.

1. 1. Diffusion
   2. Sublimation
   3. Evaporation
   4. Vaporisation

In deserts coulds do not precipitate because of _____.

1. 1. High wind velocity
   2. Low temperature
   3. Low pressure
   4. Low humidity

If we go to the Himalayas, we feel breathless because _____.

1. 1. It is very cold there
   2. The density of air is high on the hills reducing oxygen content
   3. the density of air is much less on the hills so oxygen content is reduced
   4. All of these

Cloudy nights are warmer because _____.

1. 1. Clouds prevent radiation of heat form ground to air
   2. Of the compact density of air
   3. More dust particles gather in the air
   4. Of low atmospheric pressure

In diesel engines ignition takes place by _____.

1. 1. Dynamo
   2. Electrical spark
   3. Battery
   4. Compression

Water cannot be used to extinguish fire caused by an electric current because _____.

1. 1. It may cause hydrolysis
   2. It may cause another short circuit
   3. It may cause electrocution
   4. It will spoil the wiring

Metals are good conductors of electricity because _____.

1. 1. They contain free electrons
   2. they have high melting point
   3. they atoms are lightly packed
   4. None of these

A red light is used in a traffic signal because _____.

1. 1. It is beautiful
   2. It is visible to people even with bad eyesight
   3. It has the longest wavelength and can be easily noticed from a long distance
   4. None of these

The dynamo converts _____.

1. 1. Mechanical energy into magnetic energy
   2. Electrical energy into mechanical energy
   3. Mechanical energy into electrical energy
   4. None of these

Which of the following does not admit any division?

1. 1. Molecules
   2. Atom
   3. Compound
   4. All