Solar Radiation, Heat balance and Temperature For Class 11 Geography Test Paper

Ans. (a) Isotherms

Ans. (a) Sun spots

Ans. (b) 5700 degree celcius

Ans.  (a) Winds

Ans. (b) Pyrheliometer

Ans. (a) The line joining the places of equal temperature

Ans.  (a) Long wavelengths

Ans. (a) rotation of the earth on its axis

Ans. (a) sun

Ans. (a) atmosphere

Ans. (b) Solar radiation

Ans. Wave

Ans. (a) Thiruvananthapuram

Ans.  (c) Sub-tropical areas

Ans. (a) terrestrial radiation

Ans. (b) Convection

Ans. (a) 152 million km.

Ans. (c) latitude

Ans. (c) scattering

Ans. (c) albedo

Ans. (b) 21st June

Ans. (d) all of these

Ans. (b) June 21st

Ans. (a) 85°

Ans. (a) 100 units

Ans. (d) all of these

Ans. (b) conduction

Ans. (a) conduction

Ans. The cold air acts almost like water and moves down the slope to pile up deeply in pockets and valley bottoms with warm air above. This is called air drainage. It protects plants from frost damages

Ans. The incoming solar radiation is called insolation. Insolation is * greatest at the equator. It decreases polewards. The total amount of insolation received at the equator is roughly about 4 times of that received at the poles. In tropical regions, the amount of insolation is only large but there is also little seasonal variation. It is because all their places between Tropic of Cancer and Capricorn experience overhead sun twice during the course of a year. Insolation is maximum twice in a belt between 23°30’ and 66°30′.

Ans. The energy from the sun passes through different layers of the atmosphere before it reaches the ground. Atmospheric gases are essentially transparent to visible light, but suspended particles of liquid or solid material can absorb or reflect light. A thick cloud may allow less than 10% of sunlight to reach the earth’s surface. Clouds generally behave like mirrors. They reflect sunlight off in different directions rather than absorbing. Reflected sunlight is permanently lost from the earth. The blue colour of the daytime sky is due to the scattering of sunlight.

Ans. The temperature is the measurement of available or sensible heat energy in a system. It is a measure of hotness or coldness of the body. Such property determines whether the heat will flow out or into an object when it comes in contact with other objects.

Ans. Ocean currents are large movements of ocean water from places of warm temperature to colder temperature or vice-versa. Their movement affects the temperature of the adjacent areas. The warm currents raise the temperature of adjoining colder landmasses. The climate of north-western Europe is modified to a large extent by ocean currents of the North Atlantic Ocean. The cold currents of the western coast of South Africa or South America lower the temperature of adjacent warmer lands.

Ans. The sun emits short wave radiation to space and the earth’s surface. The solar energy strikes the upper limits of the atmosphere and it gradually reaches the earth’s surface directly or indirectly (scattered) and is absorbed. It is estimated that out of 100 units of incoming solar energy, 22 units travel directly to the earth’s surface. This energy flow is called direct radiation. Some of the scattered rays eventually also find their way down indirectly to the earth’s surface. They are collectively called diffused radiation.

Ans. The amount of insolation reaching the earth’s surface depends largely on the inclination or angle of the sun’s rays. Vertical rays and those nearly 80 in the lower latitudes are more effective in increasing temperature than the oblique rays in the higher latitudes, although the duration of sunshine may be much longer in the latter case. Moreover, the oblique rays spread over a larger area on the earth’s surface whereas the vertical rays are concentrated over a smaller area, the intensity of heat being lighter in the area insolated by vertical rays.

Ans. Altitude is the height of a point above mean sea level, measured vertically. The temperature decreases with increasing height and latitude from the earth’s surface. This vertical decrease in temperature takes place at the rate of 0.65° per 100 metres or 165 metres per 1°C. These variations are normal throughout the troposphere and are termed as normal lapse rate. The atmosphere near the surface is denser and contains a large amount of water vapour and dust particles. Being closer to the land surface, it absorbs more terrestrial heat than that of the upper air. Hence, the temperature is higher in the lower part of the atmosphere than in the upper part, where the air is cleaner. That is why the higher we go, the cooler it is. Ootacamund, Mount Abu, Panchmarhi are cooler in summer than plains.

Ans. Due to the inclination of the earth’s axis, the angle of the sun’s rays falling on the earth’s surface varies from vertical on the equator to more and more slanting as one moves towards the poles. This latitudinal difference in the angle of incidence of sun’s rays leads to different amounts of insolation received at different parallels.