Correct Answer: Option A) 1 & 2
The troposphere is the lowest layer of Earth's atmosphere and is crucial for understanding weather patterns and atmospheric dynamics.
Statement 1: It extends up to 8 km at the poles and 18 km at the equator - This is correct. The troposphere's height varies with latitude due to temperature differences. At the poles, where it's colder, the troposphere extends only up to about 8 km. At the equator, where it's warmer and air expands more, it extends up to approximately 18 km. This variation is due to the difference in thermal expansion of air masses.
Statement 2: It is the layer of all weather phenomena- This is correct. The troposphere contains about 75% of the atmosphere's mass and virtually all weather phenomena occur in this layer. Clouds, precipitation, storms, and other weather events are confined to the troposphere because this layer contains most of the water vapor and experiences the most significant temperature and pressure changes.
Statement 3: Temperature increases with altitude in this layer - This is Incorrect. In the troposphere, temperature actually decreases with altitude at an average rate of about 6.5°C per kilometer (called the environmental lapse rate). This happens because the troposphere is heated primarily from below by the Earth's surface, which absorbs solar radiation and re-radiates heat.
