Textbook Solutions: The Atmosphere | Footprints Class 7: Book Solutions, Notes & Worksheets PDF Download

Tick the correct option.
Q1.
Ans: (a) 80 km

Q2.
Ans: (c) 5

Q3.
Ans: (a) 78

Q4.
Ans: (a) troposphere

Q5.
Ans: (a) tropopause

Q6.
Ans: (b) ultraviolet rays

Q7.
Ans: (c) mesosphere

Q8.
Ans: (a) Torrid, Temperate and Frigid

Q9.
Ans: (a) humidity

Q10.
Ans: (a) anemometer

II. Answer the following in one sentence.
Q1.
Ans: The major gases that constitute the atmosphere are nitrogen (78%) and oxygen (21%).

Q2.
Ans: Dust in the atmosphere acts as condensation nuclei around which evaporated moisture condenses, leading to cloud formation.

Q3.
Ans: Noctilucent clouds are thin, wispy clouds that form in the mesosphere and are visible during twilight.

Q4.
Ans: Insolation refers to solar radiation received by the Earth.

Q5.
Ans: Temperature is measured using a thermometer.

III. Answer the following questions in brief.
Q1.
Ans: The heat zones of the world are Torrid Zone (between Tropic of Cancer and Tropic of Capricorn), Temperate Zone (between Tropic of Cancer and Arctic Circle in the northern hemisphere and Tropic of Capricorn and Antarctic Circle in the southern hemisphere), and Frigid Zone (between Arctic Circle and North Pole in the northern hemisphere and Antarctic Circle and South Pole in the southern hemisphere).

Q2.
Ans: Atmospheric pressure is affected by altitude, temperature, moisture, and the rotation of the Earth.

Q3.
Ans: Local winds are small-scale winds caused by local temperature variations and are often seasonal in nature.

Q4.
Ans: A cyclone is a whirling mass of air that develops into a storm around a low-pressure system, accompanied by torrential rain and thunderstorms.

Q5.
Ans: Precipitation is the process by which water droplets in clouds become too heavy and fall to the ground as rain, snow, hail, or sleet. There are three kinds of precipitation: relief precipitation, convectional precipitation, and cyclonic precipitation.