The Green House Effect is caused by an excess of _____.

1. 1. Carbon monoxide
   2. Carbon tetrachloride
   3. Carbon dioxide 
   4. None of the above

T.V. transmission cannot cover a very large area because _____.

1. 1. the strength of TV waves is very limited
   2. picture cannot be transmitted clearly after a specific distance
   3. the air is not a good conductor of light and sound/waves
   4. the shape of the earth is spherical

How much amount of water does the cow’s milk contain in terms of percentage?

1. 1. 60 %
   2. 80%
   3. 70%
   4. 50%

Most of the ozone in the atmosphere is concentrated in the _____.

1. 1. Stratosphere
   2. Mesosphere
   3. Ionosphere
   4. Troposphere

An iceberg is floating in sea. How much of its mass will remain above the surface of water?

1. 1. One fifth
   2. One third
   3. One fourth
   4. One tenth

An astronaut inside a spacecraft is in a state of weightlessness. This implies that _____.

1. 1. the mass of the astronaut is reduced to zero
   2. gravity inside the spacecraft ceases to act
   3. the astronaut and the spacecraft are both in a free-falling state
   4. the astronaut is outside the influence of the earth’s gravitational force

The sun appears red at sunrise and sunset while it appears white at noon, because _____.

1. 1. of refraction
   2. of scattering of light due to dust particles and air molecules 
   3. it is cooler at sunrise and at sunset
   4. of diffraction leading to red end of the spectrum reaching the earth

A lake starts freezing because of the cold atmosphere. It will first freeze _____.

1. 1. at the top surface
   2. at the bottom
   3. in the middle part
   4. uniformly throughout the water body

The beautiful colour patterns exhibited by a peacock in its tail feathers are due to _____.

1. 1. Selective reflection of light
   2. Selective absorption of light
   3. Sinterference of light
   4. Natural colour pattern of feathers

What is the average adult pulse rate?

1. 1. 72-80
   2. 140-150
   3. 60
   4. 115-125