Air containing water vapour is …………… than dry air.

1. Denser
2. Lighter
3. Heavier
4. Thinner

At what height is the troposphere above sea level?

1. 14 km
2. 16 km
3. 18 km
4. 12 km

The atmospheric layer which reflects the low frequency radio waves but absorbs the medium and high frequency waves

1. Exosphere
2. Ionosphere
3. Thermosphere
4. Mesosphere

The layer that protects us from the ultraviolet rays of the sun

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