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What is insolation?

• The amount of heat stored in the Earth's core

• The incoming solar radiation received by the Earth's surface

• The reflection of heat back into space by clouds

• The movement of ocean currents due to wind

Answer explanation

Explanation: Insolation is the amount of sunlight that reaches a certain area on Earth. It affects temperatures, weather, and climate.
Example: A sunny beach receives a lot of insolation, making the sand very hot during the day.

Which of the following factors affects the amount of insolation received at different locations on Earth?

• Latitude

• Time of year

• Angle of the Sun’s rays

• All of the above

Answer explanation

Explanation: Insolation depends on location, time of year, and the angle at which sunlight hits the surface.
Example: The equator gets more sunlight year-round, while the poles get very little in winter.

What is planetary albedo?

• The process of heat absorption by the oceans

• The proportion of solar radiation reflected by Earth back into space

• The amount of greenhouse gases in the atmosphere

• The amount of radiation received at the equator

Answer explanation

Explanation: Some surfaces reflect sunlight instead of absorbing it. The more a surface reflects, the higher its albedo.
Example: Snow and ice reflect most sunlight, keeping polar regions cooler.

Which surface has the highest albedo?

• Oceans

• Forests

• Snow and ice

• Desert sand

Answer explanation

Explanation: Bright surfaces like snow and ice reflect most of the sunlight, reducing heat absorption.
Example: If you wear a white shirt on a sunny day, it reflects heat and keeps you cooler than a black shirt.

What percentage of incoming solar radiation is reflected back to space by the Earth's surface and atmosphere?

• 10%

• 31%

• 50%

• 80%

Answer explanation

Explanation: About one-third of the sunlight reaching Earth is reflected by clouds, ice, and the atmosphere.
Example: On a cloudy day, more sunlight is reflected, making it cooler.

What is the greenhouse effect?

• The trapping of heat in the Earth’s atmosphere by greenhouse gases

• The loss of heat from the Earth's core into space

• The absorption of solar radiation by plants

• The increase in Earth's temperature due to deforestation

Answer explanation

Explanation: Greenhouse gases like carbon dioxide (CO₂) and water vapor trap heat, keeping Earth warm.
Example: A car parked in the sun gets hotter inside because heat is trapped by the windows—just like greenhouse gases trap heat in the atmosphere.

Which gas is the most significant contributor to the natural greenhouse effect?

• Oxygen

• Nitrogen

• Carbon dioxide

• Hydrogen

Answer explanation

Explanation: CO₂ absorbs heat and keeps the planet warm, making it a key greenhouse gas.
Example: Burning fossil fuels like coal and gas releases CO₂, increasing global temperatures.

What happens to the Earth's energy balance if the greenhouse effect increases?

• More heat escapes into space

• The Earth's temperature rises

• The planetary albedo increases

• The amount of insolation decreases

Answer explanation

Explanation: More greenhouse gases trap extra heat, leading to global warming.
Example: More CO₂ from factories and cars causes rising temperatures, melting glaciers, and extreme weather.

What is meant by a "deficit of radiation"?

• When less radiation is emitted from the Earth than received

• When more radiation is absorbed by the surface than emitted

• When there is a shortfall in the energy received versus energy lost

• When radiation levels become harmful to living organisms

Answer explanation

Explanation: Some areas (like the poles) lose more heat than they receive from the Sun, leading to a radiation deficit.
Example: Arctic regions remain cold because they lose more heat than they gain from sunlight.

Where is there a net radiation deficit on Earth?

• At the equator

• At high latitudes (polar regions)

• In desert regions

• Over oceans

Answer explanation

Explanation: The poles get less sunlight but lose a lot of heat, creating an energy deficit.
Example: This is why Greenland and Antarctica remain frozen.