Important Questions Test: Winds Storms & Cyclones - Class 7 MCQ

Warm air rises higher. This is because gases expand more when they absorb heat further.

An anemometer is a device used for measuring wind speed.

The 'eye of a cyclone is the least pressure area with very high speed winds revolving around it.

This is because the descending winds in the cyclones's eye don't reach near the surface. They get adiabatically warmed up on descending and start rising again without reaching the surface. Hence the low pressure in the cyclone's eye persists and gets intensified. 

The photographs taken by the satellites help in detecting cyclones.

Lightning hits tall structures, water and metallic bodies easily. So, avoiding them will be safer.

The energy contained in the gaseous form (vapour) is more than the energy contained in the liquid form (water). Therefore, when vapour changes to water it loses some heat.

Sea and land breezes are caused because of the uneven heating of the earth through convection currents.

Winds that are cold usually show lateral (sideways) movement while the ones that are warm show vertical movement. Since, the winds blow from the north and the south towards the equator, it must be hotter than the other places.

The rotation of the earth from west to east (pulls) changes the north-south winds to northeast-southwest direction and the south-north winds to southeast-northwest direction.

When a vehicle moves very fast, a low pressure is produced temporarily and the wind nearby rushes in to fill its place.

The winds coming from the southwest blow over the Indian ocean and bring lots of rains.

Upon heating, the molecules in the gases go further away from each other and thus become lighter.

When winds blow over a weak thatched roof, it creates a low pressure over it and a high pressure inside the hut causing the roof to blow off. Opening the doors and windows reduces this pressure difference and prevents the roof from being blown off.

Only Indonesia is nearer to the sea and most likely to be affected by cyclones.

Pressure is highest in a bottle or any container which is closed.

A drinking straw is used by creating a suction with your mouth. Actually this causes a decrease in air pressure on the inside of the straw. Since the atmospheric pressure is greater on the outside of the straw, liquid is forced into and up the straw.

Evaporation causes an increase in humidity, the amount of water vapour present in the air. Formation of dew drops on leaves is the result of condensation and not of evaporation.

Change of water vapour to water (condensation) takes place at a low temperature. Since, clouds are formed high up in the air, we can conclude that temperature decreases as we go higher in the atmosphere.

The difference of air pressure between the surface of the liquid and inside the straw or an ink filler pushes the liquid up. Hence, both of them work on atmospheric pressure.

Warm air is lighter than cold air because the air in contact with the hot surface of the earth gets heated up, so it expands and becomes lighter.