Climatology in Geography Questions and Answers

Answer: D

(A) is true, but (R) is false.

Wet clothes do take longer to dry on a humid day. Drying depends on evaporation, and the amount of water that can evaporate depends on how much more water vapour the air can hold.

On a humid day the air already holds a lot of water vapour, close to saturation, so the rate of evaporation decreases, not increases. That is exactly why the clothes dry slowly. So the reason states the opposite of the truth, which rules out the options calling both statements true, and the option calling both false.

Answer: A

Both (A) and (R) are true and (R) is the correct explanation of (A).

The polar easterlies blow out from the polar high-pressure belt towards the sub-polar low. Moving from the pole towards lower latitudes, they are deflected to the right in the northern hemisphere, which is why they blow from the east.

The deflection is caused by the Earth's rotation on its axis, the Coriolis effect, which turns moving air to the right in the northern hemisphere and to the left in the southern. So the reason gives the cause of the behaviour the assertion describes, which rules out the option saying it does not explain A and the options calling either statement false.

Answer: D

The answer is Neither 1 nor 2.

The India Meteorological Department's criteria are the other way round. A heat wave is considered when the maximum temperature of a station reaches at least 40 °C for the plains and at least 30 °C for hilly regions (with further conditions on the departure from normal). Statement 1 gives 30 °C for the plains and statement 2 gives 40 °C for the hills, so both are wrong.

The trap is that both figures are real thresholds, but swapped.

Answer: B

Evergreen trees grow near the equator because of heavy rainfall and high temperature.

The equatorial region is hot and receives heavy rainfall throughout the year. With no dry or cold season, trees never need to shed their leaves to conserve water, so the forests stay green all year round; these are the tropical evergreen (rain) forests.

Moderate temperature and rainfall support deciduous or mixed forests. Low rainfall with high temperature produces thorny bushes and desert vegetation, and low temperature with moderate rainfall suits coniferous forests, not equatorial evergreens.

Answer: C

The reason is that the stratosphere is free from clouds and related weather phenomena.

The stratosphere lies above the troposphere and extends up to about 50 km. Clouds, rain, storms and other weather phenomena occur in the troposphere, so the stratosphere above is almost free of them. That gives calm, clear conditions ideal for aircraft.

Air pressure, high or low, is not the reason given for its suitability, and the troposphere, not the stratosphere, is where windy and turbulent conditions occur.

Answer: D

The correct option is A-III, B-IV, C-I, D-II.

• The ozone layer is in the stratosphere and protects us from ultraviolet rays.
• Radio transmission is helped by the thermosphere (its ionosphere reflects radio waves back to Earth).
• Weather phenomena such as rain, fog and hailstorms occur in the troposphere.
• The exosphere, the uppermost layer, has very thin air.

Option B lists the layers in their natural order without matching them, and options A and C misplace the ozone layer.

Answer: B

The most important factor is insolation, the incoming solar radiation.

The Sun is the source of almost all the heat at the earth's surface. How much of its energy a place receives depends on the angle of the Sun's rays and the length of the day, which change with latitude. That is why temperature generally falls from the equator towards the poles, and insolation is treated as the primary control of the distribution of temperature.

Seasons are themselves a result of changing insolation over the year, so they are not the underlying factor. Crowded high-rise buildings and asphalt roads only raise temperatures locally, as in an urban heat island, and do not decide the temperature pattern of the earth.

Answer: C

Land and sea breezes are local winds.

They blow over a small coastal area and reverse every day. By day the land heats faster than the sea, so the air over the land rises and cooler air moves in from the sea as a sea breeze. At night the land cools faster, and the breeze blows from land to sea instead.

Permanent winds, such as the trade winds, westerlies and polar easterlies, blow in the same direction all year over large belts of the earth. Seasonal winds, such as the monsoons, change direction with the season, not every day. A cyclone is a storm system that forms around a centre of low pressure, not a class of wind like the others.

Answer: B

The keyed answer is Both A and R are true but R is not the correct explanation of A.

A is true: the area between the Tropic of Cancer and the Arctic Circle (and its southern counterpart) is the temperate zone, with moderate temperatures. R is also true: the mid-day sun is directly overhead only between the two tropics, so it never shines overhead on any latitude beyond the Tropic of Cancer.

The key does not accept R as the explanation because R is equally true of the frigid zone beyond the Arctic Circle, which is extremely cold, not moderate. What makes the temperate zone moderate is that the sun's rays there fall at an intermediate angle, more slanting than in the tropics but less than near the poles; R on its own does not say that. The options calling A or R false are wrong, since both statements are accurate.

Answer: C

A is correct and R is incorrect, so the answer is A is correct but R is incorrect.

When air is heated it expands, so the same mass occupies more space. Its density falls, and the lighter warm air rises while cooler, denser air sinks and flows in to take its place. This is how convection currents and land and sea breezes form.

So hot air is less dense than cold air, not denser, and R is false. Because R is false, it cannot be the explanation of A, which rules out the first two options. A itself is the familiar fact behind hot-air balloons, so 'A is incorrect' is also wrong.