Important Questions and Answers for Class 11 Geography Chapter 8 Solar Radiation Heat Balance and Temperature 2025-26

Q1. The sun is directly overhead at noon on 21st June at:

• (a) The equator
• (b) 23.5° S
• (c) 23.5° N
• (d) 66.5° N

Answer: (c) 23.5° N. 

On 21st June, the sun is overhead at the Tropic of Cancer (23.5° N) due to the tilt of Earth's axis.

Q2. In which one of the following cities are the days the longest?

• (a) Tiruvanantpuram
• (b) Chandigarh
• (c) Hyderabad
• (d) Nagpur

Answer: (b) Chandigarh. 

Being farthest north among the options, Chandigarh experiences the longest days in summer.

Q3. The atmosphere is mainly heated by the:

• (a) Short wave solar radiation
• (b) Reflected solar radiation
• (c) Long wave terrestrial radiation
• (d) Scattered solar radiation

Answer: (c) Long wave terrestrial radiation. 

The atmosphere absorbs more heat from Earth's re-radiated long wave energy than direct solar radiation.

Q4. The main reason that the earth experiences highest temperatures in the subtropics in the northern hemisphere rather than at the equator is:

• (a) Subtropical areas tend to have less cloud cover than equatorial areas.
• (b) Subtropical areas have longer day hours in the summer than the equatorial.
• (c) Subtropical areas have an enhanced “green house effect” compared to equatorial areas.
• (d) Subtropical areas are nearer to the oceanic areas than the equatorial locations.

Answer: (a) Subtropical areas tend to have less cloud cover, so more solar radiation reaches the surface, causing higher temperatures than at the equator which is usually cloudy.

2. Very Short Answer (VSA).

Q1. What is insolation?

Answer: Insolation is the incoming solar radiation that reaches the Earth's surface in the form of short waves from the sun, delivering energy for Earth's climate and life processes.

Q2. Name two processes by which the lower atmosphere is heated after the earth absorbs insolation.

Answer: The lower atmosphere is mainly heated by conduction and terrestrial radiation after the Earth's surface absorbs insolation from the sun.

Q3. Define albedo.

Answer: Albedo is the proportion or percentage of incoming sunlight that is reflected by a surface, like clouds or snow, back into space.

3. Short Answer Questions.

Q1. Explain why maximum insolation is received over subtropical deserts and not at the equator.

Answer: Subtropical deserts get maximum insolation due to clear skies and minimal cloud cover, allowing more sunlight to reach the surface. At the equator, frequent cloudiness reduces sunlight received. Thus, deserts like the Sahara have higher solar radiation compared to equatorial regions.

Q2. List four factors that affect temperature distribution on Earth’s surface.

Answer: The four main factors are latitude, altitude, distance from the sea, and the presence of ocean currents or air-mass circulation. Each contributes to variations in temperature by influencing heat absorption and redistribution at different places.

Q3. Give one example of temperature inversion in day-to-day life.

Answer: A common temperature inversion occurs during winter nights when cool air gets trapped beneath warmer air, causing dense morning fog and the accumulation of smoke and dust near the ground, especially in valleys or low-lying areas.

4. Long Answer Questions.

Q1. Discuss in detail the process of heat budget and its importance for Earth's temperature stability.

Answer: The heat budget is the balance between incoming solar energy (insolation) and outgoing terrestrial radiation. About 100 units of solar energy reach the top of the atmosphere. Roughly 35 units are reflected or scattered, and 65 units are absorbed by the earth-atmosphere system. Earth reradiates these absorbed units as long-wave energy. The balance ensures Earth does not keep heating up or cooling down over time, maintaining a relatively stable climate, which supports life.

1. Solar insolation reaches Earth; part is reflected, part absorbed
2. Absorbed energy is reradiated as long-wave terrestrial radiation
3. Outgoing radiation matches incoming, creating heat balance

Q2. Analyze why temperature ranges are higher in interiors of continents than coastal areas, with examples.

Answer: Continental interiors, like the Siberian plains, have higher temperature ranges because land heats up and cools down more rapidly than water, leading to hot summers and extremely cold winters. Coastal regions experience moderate temperatures due to the sea’s slow heating and cooling, keeping daily and annual ranges lower. This is evident in New Delhi (interior) vs. Mumbai (coastal).

1. Land’s specific heat is lower than water’s
2. Water moderates nearby temperatures year-round
3. Distance from sea causes more extreme climates inland

Q3. Explain how the atmosphere is indirectly heated by the Earth and why this process is important for climate.

Answer: The Earth's surface absorbs insolation and then re-emits it as long-wave terrestrial radiation. The atmosphere, though largely transparent to incoming short-wave sunlight, absorbs much of this terrestrial radiation, especially through greenhouse gases. This indirect heating keeps the lower atmosphere warm at night, preventing extreme cooling and making the climate habitable.

1. Surface absorbs solar radiation
2. Re-emits it as long-wave energy
3. Atmosphere (mainly CO₂, vapor) absorbs this

5. Assertion–Reason type questions.

Assertion (A): During winter nights, cold air collects in valleys leading to increased chances of frost.
Reason (R): Cold air is heavier than warm air and flows down slopes under gravity.

• (a) A and R are true, and R is the correct explanation of A
• (b) A and R are true, but R is not the correct explanation of A
• (c) A is true, but R is false
• (d) A is false, but R is true

Answer: (a) Both statements are true and the reason correctly explains the assertion based on the concept of cold air drainage.

Assertion (A): The highest temperature range is observed over the north-eastern part of Eurasian continent.
Reason (R): Water heats up and cools down quickly compared to land.

• (a) A and R are true, and R is the correct explanation of A
• (b) A and R are true, but R is not the correct explanation of A
• (c) A is true, but R is false
• (d) A is false, but R is true

Answer: (b) Both statements are true, but the reason is not a correct explanation; land, not water, heats/cools quickly, causing higher range.

3. Fill in the Blanks Questions.

Q1. The rate at which temperature decreases with height in the atmosphere is known as the _______ _______ _______.

Answer: The normal lapse rate. 

It is the standard rate of 6.5°C decrease in temperature per 1,000 meters of altitude rise in the troposphere.

Q2. The reflected portion of incoming solar radiation is called the _______ of the earth.

Answer: Albedo. 

It is the fraction or percentage of solar energy that is reflected by Earth's surface or atmosphere back into space.

Q3. The process by which heat is transferred through horizontal movement of air masses is _______.

Answer: Advection. 

It refers to horizontal transfer of heat by wind, significantly affecting temperature patterns, especially in mid-latitudes.

Benefits of Learning Solar Radiation, Heat Balance and Temperature for Class 11

Studying class 11 geography chapter 8 important questions Solar Radiation, Heat Balance and Temperature helps you understand why climates vary across the globe. These concepts lay the foundation for advanced topics and improve your ability to solve chapter 11 geography test questions confidently.

Focusing on class 11 geography chapter 8 important question answer builds a strong conceptual base. You’ll gain clarity on heat transfer, temperature controls, and atmospheric processes, which are vital for success in school and future studies of weather and climate.