Consider the following statements regarding ‘fronts’: 1. The movement of a front causes a slow change in weather in the area over which it moves. 2. Cold fronts are associated with thunderstorms. 3. Warm front is the boundary between an advancing mass of warm air where it is overriding and rising above a mass of colder air. Which of the statements given above is/are correct?
- (a)1 only
- (b)1 and 2 only
- (c)2 and 3 only
- (d)1, 2 and 3
Correct — C, statements 2 and 3 only. Statement 1 is false — because a front is a sharp boundary between two contrasting air masses, its passage brings a relatively rapid and marked change in weather (temperature, pressure, wind, cloud and rain), not a slow change. Statement 2 is true, as a cold front pushes under and lifts the warm air steeply, building cumulonimbus and triggering thunderstorms. Statement 3 correctly defines a warm front as the boundary where an advancing warm air mass overrides and rises above a colder air mass. So only 2 and 3 are correct.
- (a)1 only — This keeps the false statement 1 and wrongly drops the two correct statements about cold and warm fronts.
- (b)1 and 2 only — This includes the false statement 1 and omits the correct warm-front definition in statement 3.
- (d)1, 2 and 3 — This includes statement 1, but a front brings a rapid — not slow — change in weather.
A front is the sloping boundary surface between two air masses of different temperature and humidity. At a cold front, denser cold air undercuts warm air and forces it up steeply, giving a narrow band of towering cumulonimbus, showers and thunderstorms followed by a sharp temperature drop. At a warm front, lighter warm air glides up over retreating cold air along a gentle slope, giving a wide belt of layered cloud and prolonged, steady rain. Fronts are the organising feature of temperate (extratropical) cyclones.
Statement 1 is the distractor — a front is precisely where weather changes sharply, so the phrase 'slow change' is the tell-tale error, and cold fronts change the weather most abruptly of all. Statements 2 and 3 are textbook-correct, so eliminating statement 1 fixes the answer at 2 and 3.
- A cold front, with its steep slope, produces cumulonimbus, showers and thunderstorms and a sudden fall in temperature.
- A warm front, with its gentle slope, brings wide layered cloud and steady, prolonged rain as warm air rises over cold.
- An occluded front forms when a faster-moving cold front overtakes a warm front.
- Fronts are central to mid-latitude (temperate) cyclones and their orderly weather sequence.
Statements 2 and 3 are correct; statement 1 is false because a front brings a rapid, not slow, weather change.
- Thinking fronts change weather slowly — cold fronts especially bring abrupt change.
- Swapping the signatures of a warm front (steady, layered rain) and a cold front (showery thunderstorms).
- Confusing a temperate/frontal cyclone with a tropical cyclone, which has no fronts.
Front questions test the cold-versus-warm signature (slope, cloud, rain) and the fact that a front marks a sharp, not gradual, change in weather.
No directly related past PYQ was found.
- practice — not a real PYQ
Thunderstorms with towering cumulonimbus and a sudden temperature drop are most characteristic of a
- (a)Warm front
- (b)Cold front
- (c)Stationary front
- (d)Occluded front
Answer(b) Cold front — cold air undercuts and lifts warm air steeply, building cumulonimbus and thunderstorms.
- practice — not a real PYQ
A front is best defined as the boundary between
- (a)two ocean currents
- (b)two air masses of different temperature and humidity
- (c)land and sea breezes
- (d)the troposphere and the stratosphere
Answer(b) two air masses of different temperature and humidity — the sloping surface separating them.