Physical Geography
Physical Geography in Madhyamik tests how exogenetic forces shape the land and how the atmosphere behaves: weathering, the work of rivers, glaciers, wind and groundwater, and the structure, temperature, pressure and moisture of the atmosphere. Marks go to correct process vocabulary and a correct cause-and-effect sequence, not to pure description.
Process vocabulary that earns marks
- Weathering is breakdown in situ; erosion is removal and transport by a mobile agent. Never write "wind weathering" when you mean abrasion.
- River work: hydraulic action, corrasion, attrition, solution. Deposition follows a fall in velocity, gradient or load competence.
- Glaciers erode by plucking and abrasion, producing cirque, arête, hanging valley, U-shaped valley and moraine.
- Wind: deflation, abrasion, attrition; yardang, mushroom rock, barchan, seif.
- Groundwater: carbonation on limestone; sinkhole, cavern, stalactite (from the roof), stalagmite (from the floor).
Atmosphere rules
- The troposphere holds weather; temperature falls at the normal lapse rate of about 6.5 °C per km.
- Pressure belts shift with the sun; the migrating ITCZ is what drives the Indian monsoon.
- Relative humidity rises on cooling even when the actual vapour content is unchanged.
Worked example
Sea-level temperature is 30 °C. At 4,000 m: 30 − (6.5 × 4) = 30 − 26 = 4 °C. Multiply the lapse rate by the height in km first, then subtract - step marks are given for that order. If the rising air becomes saturated, condensation releases latent heat and the saturated lapse rate applies, so cloud is expected.
Traps
Weathered material stays where it formed; eroded material moves. Stalactites hang, stalagmites rise. A hanging valley is a tributary valley, not the main trough. Do not replace a supplied lapse rate of 6.5 °C/km with 1 °C per 100 m; use the figure in the question.