Insolation and factors affecting it

Clouds reduce solar energy by day and reduce heat loss by night. This can lower the daily temperature range.

Clear dry air allows more daytime insolation and more nighttime heat loss. Thus desert temperature range can be high.

The solar constant represents the average rate at which solar energy is received on a unit area oriented perpendicular to the Sun’s rays at the Earth–Sun distance. If this constant decreases, the incoming solar energy available to Earth decreases directly, assuming other conditions remain unchanged. Before energy reaches the ground, the atmosphere and surface may further absorb, reflect, or scatter it, but the initial supply from the Sun has already become smaller.

Option A is correct because it states that the rate of received solar energy will fall. Options B and C describe changes in Earth’s rotation or day length, which do not follow directly from a change in the solar constant. Option D is also incorrect because albedo is a property of a surface or planetary system and does not automatically become zero when incoming solar energy changes.

Low albedo increases absorption but high heat capacity slows temperature rise. Understand both factors separately.

Vertical rays are favourable, but clouds and albedo can reduce energy gain. In hard questions, compare opposing factors.

Rays are more direct in the tropics, but local factors change temperature. Thus insolation and temperature can differ.

Atmospheric components modify incoming radiation before it reaches the surface. This affects the surface energy budget.

At altitude sunlight can be stronger while air can be thin and cool. Understand insolation and air temperature separately.

Insolation gives energy, but albedo, heat capacity, moisture, and clouds change the temperature response. This is the basis of geographic analysis.

Low atmospheric obstruction and long day bring more energy. Low albedo makes more of that energy absorbed.

Oblique rays spread energy, fog blocks energy, and high albedo returns energy. This is a strong low-heating combination.

A moist surface may have more evaporation and part of the heat is used in it. Therefore temperature may rise slowly.

In the Northern Hemisphere, a south-facing slope is often more sun-facing. This can increase local insolation and temperature.

The Equator has high Sun angle, but clouds can reduce direct radiation. In a clear desert, more direct insolation may reach the surface.

A black road absorbs more while grass can have evaporation and different reflection. Therefore temperature response differs.

The direct answer is A: scattering and absorption of radiation. Insolation means incoming solar radiation received by Earth’s surface. Persistent haze contains tiny particles, droplets and other suspended material. Step by step: sunlight travels through the hazy atmosphere; some radiation is scattered in different directions; some is absorbed by particles or moisture; therefore less direct solar energy reaches the crop field. The surface may still receive diffuse light, but total or direct insolation can be reduced. A is correct. B is wrong because an ocean tide is the periodic rise and fall of sea level caused mainly by gravitational effects, not the process that blocks sunlight in haze. C is wrong because seismic waves come from earthquakes and do not explain reduced sunlight. D is wrong because river deposition is the laying down of sediments and is unrelated to atmospheric radiation. Memory cue: haze in the air means solar rays are scattered or absorbed before reaching the ground.

A long day increases receiving time, but dense clouds can stop energy from reaching the surface. So the total effect decreases.

At equinox day and night are balanced, but Earth's curvature makes ray angle change with latitude. Thus insolation can remain unequal.

Earth-Sun distance slightly changes insolation. But seasons are controlled by axial tilt through day length and ray angle.

Part of the energy on a wet surface can be used in evaporation. Therefore temperature rise can be lower under equal insolation.

Clear sky and vertical rays give more energy. Still albedo, heat capacity, and moisture can control final temperature.

Sun-facing aspect increases insolation, but snow can return much energy. So check both slope aspect and surface albedo.

Clouds and water vapour can block or absorb radiation. Thus less energy reaches the surface and temperature rise can be limited.

For high insolation rays should be direct, sky clear, and receiving time long. Low atmospheric obstruction is also important.

Insolation is affected by ray angle, day length, clouds, dust, moisture, and surface properties together. Combined analysis is essential in hard questions.