Weather and Climate — Important Questions

Cirrus

Step 1: Cirrus clouds are high-altitude clouds that form between 5 to 10 km above the earth. Step 2: They are made of tiny ice crystals (not water droplets) because the temperature is very cold at that height. Step 3: They appear feathery or fibrous, like wisps of cotton floating in the sky. Step 4: Cumulus clouds are cauliflower-shaped with great vertical height — not feathery. Stratus clouds are sheet-like clouds at low levels. Nimbus clouds are dark rain clouds. Step 5: So the correct answer is Cirrus.

Wind speed

Step 1: Wind has two important properties — direction and speed. Different instruments measure each. Step 2: An anemometer measures wind speed. It has 3 or 4 metal cups mounted on a pole that spin when wind blows. The faster they spin, the stronger the wind. Step 3: Wind speed is measured in knots. (1 knot = 1 nautical mile per hour). Step 4: Wind direction is measured by a wind vane (or weather cock), not an anemometer. Step 5: Rainfall is measured by a rain gauge, and atmospheric pressure is measured by a barometer — both different instruments.

1013 millibars

Step 1: Atmospheric pressure is measured in millibars (mb) by meteorologists. Step 2: At normal sea level, the standard atmospheric pressure is 1013 millibars. Step 3: This 1013 mb is equivalent to 76 cm of mercury column in a mercury barometer. Step 4: Option A (1034) is a distractor — 1034 gm/sq cm refers to the mass of air, not the mb pressure value. Step 5: 760 refers to millimetres of mercury (76 cm), not millibars. 101 is not a standard measurement used in meteorology for sea level pressure.

To the right

Step 1: The Earth rotates at different speeds at the equator and at mid-latitudes. Step 2: This difference in speed creates a force called the Coriolis force, described by Ferrel's Law. Step 3: Due to this force, winds do not blow in a straight line — they get deflected. Step 4: In the Northern Hemisphere, winds are deflected to the RIGHT of their original direction. Step 5: In the Southern Hemisphere, winds are deflected to the LEFT. This is an important rule for understanding global wind patterns.