Temperature | Class 7 | Social Science | C9

Temperature 

M.P. Board Class 7th Social Science 

 9

Temperature

Online Lecture

Textual Exercise

Choose the correct alternative from the following: 

1. The temperature decreases 1°C at the height of:

(a) 165 m

(b) 156 m

(c) 161 m

(d) 561 m

Ans. (a) 165 m

2. The process of rising up of air after heating is known as:

(a) Radiation

(b) Isolation

(c) Convection

(d) Reflection.

Ans. (c) Convection

Fill in the blanks:

1. The heat radiated by the sun is called …………….
2. The heat re-radiated by the earth is called ……………..
3. The difference between maximum and minimum temperature is known as …………..

Ans.

1. radiation
2. Terrestrial radiation
3. diurnal range of temperature.

Short Answer Type Questions

1. What is temperature?

Ans. The degree of coldness or hotness in the air is known as temperature.

2. What are the three processes by which air is heated?

Ans. The three processes by which air is heated are:

1. Isolation
2. Radiation
3. Convection

3. What is the difference between solar isolation and terrestrial radiations?

Ans. The heat emitted-by the sun is called solar isolation, whereas the heat radiated back by the earth is called terrestrial radiation.

Long Answer Type Questions

 

1. Describe the factors which affects the temperature.

Ans. The factors which affect the temperature are:

1. The angle made by sun’s rays – The atmosphere surrounding the earth is circular. The rays coming from the sun is generally straight but due to the spherical shape of the earth, it reaches at different places in different angles. The rays of the sun falls vertical at the equator and slanting at the poles. The vertical rays fall over a short area and therefore receives more heat. The slanting rays of the sun have less heat.

2. The distance traveled by the sun’s rays in the atmosphere – The vertical rays of the sun have to pass through a short distance while the slanting rays have to cover a longer distance. As a result the intensity of the heat is higher in the first case and lower in the second case.

3. Height from Sea level – The temperature falls when we move higher from the sea level. The mountains are cooler than plains.

4. Duration of the day – The longer the duration of the day the greater is the isolation and die shorter the duration of the day the smaller will he the isolation.

2. Explain an ordinary thermometer by illustrations.

Ans. The instrument used to measure temptation is known as thermometer. The measuring unit of temperature is centigrade.