The question asks for the approximate standard atmospheric pressure at an altitude of 5 km. This requires knowledge of the standard atmospheric pressure profile with altitude, which is a common concept in meteorology and atmospheric science.
A) 540 mb is the correct answer. According to the International Standard Atmosphere (ISA) model, the atmospheric pressure at 5 km altitude is approximately 540.48 mb, which rounds to 540 mb.
The question asks for the standard atmospheric pressure at an altitude of 10 km. This requires knowledge of the standard atmospheric pressure profile with altitude, which is a common concept in meteorology and atmospheric sciences.
Correct Option: B) 265 mb. This value is consistent with the International Standard Atmosphere (ISA) model for pressure at 10 km altitude.
The question asks to identify what 'isobars' represent on a weather map. This is a fundamental concept in meteorology and geography. We need to recall the definitions of various isolines used in weather mapping.
Correct Option: A) Equal atmospheric pressure
Isobars are indeed lines on a weather map that connect places having equal atmospheric pressure. This is a standard definition in meteorology.
The question asks why station-level pressure readings are adjusted to sea level for weather maps. This adjustment is crucial for accurate weather analysis, as atmospheric pressure naturally decreases with altitude. To understand the spatial distribution of pressure and identify pressure systems (highs and lows), all readings must be compared from a common reference level.
Correct Option: C) To eliminate the effect of altitude on pressure readings. This is the primary reason for reducing station-level pressure to sea level. It ensures that pressure variations shown on weather maps reflect actual atmospheric conditions rather than topographical differences.
The question asks to identify the characteristic feature of a low-pressure system on a weather map. This requires understanding how pressure systems are represented using isobars.
Correct Option: C) Isobars with lowest pressure at the centre
This option accurately describes a low-pressure system. In such a system, the atmospheric pressure decreases towards the center, leading to inward-spiraling winds (in the Northern Hemisphere, counter-clockwise; in the Southern Hemisphere, clockwise) and often associated with cloudy weather and precipitation.
Atmospheric pressure is determined by the weight of the air column above a given point. The denser and taller the air column, the higher the pressure. We need to identify the location where the maximum amount of air is above it.
Correct Option: A) At sea level. Atmospheric pressure is highest at sea level because it is the lowest point, meaning the entire column of the atmosphere is pressing down on it. As altitude increases, the amount of air above a point decreases, and the air becomes less dense, leading to lower pressure.