NCERT Solutions for Class 9 Social Science Geography Chapter 4 Climate
Ans. (a) Mumbai (Only coastal city)
Q. Study the picture and answer the question that follows:
What types of atmospheric conditions are representing over the Indian subcontinent in the given map?
(a) Atmospheric conditions over the Indian subcontinent in the month of January
(b) Atmospheric conditions over the Indian subcontinent in the month of June
(c) Atmospheric conditions over the Indian subcontinent in the month of September
(d) Atmospheric conditions over the Indian subcontinent in the month of July
Ans. (a) Atmospheric conditions over the Indian subcontinent in the month of January
Q. _________refers to the sum total of weather conditions over a long period of time.
Ans. _________refers to the condition of the atmosphere over an area at any point of time.
Q. The world is divided into a number of _________regions.
Q. Name the elements of weather and climate.
Ans. Temperature, atmospheric pressure, wind, humidity and precipitation.
Q. What is a Coriolis force?
Ans. An apparent force caused by the earth’s rotation. The Coriolis force is responsible for deflecting winds towards the right in the northern hemisphere and towards the left in the southern hemisphere. This is also known as ‘Ferrel’s Law’.
Q. What do you understand by the Inter Tropical Convergence Zone?
Ans. The Inter Tropical Convergence Zone (ITCZ,) is a broad trough of low pressure in equatorial latitudes. This is where the northeast and the southeast trade winds converge. This convergence zone lies more or less parallel to the equator but moves north or south with the apparent movement of the sun.
Q. Explain the term ‘Monsoon’.
Ans. The word monsoon is derived from the Arabic word ‘mausim’ which literally means season. ‘Monsoon’ refers to the seasonal reversal in the wind direction during a year. The climate of India is described as the ‘monsoon’ type. In Asia, this type of climate is found mainly in the south and the southeast.
Q. Study the climatic data below and answer the following questions:
|Temperature in °C||14.0||15.5||24.1||32||33||33.6||30.2||28.6||27.5||25.1||18.1||15.2|
|Rainfall in (mm)||2.5||2||2||2.5||2.7||7.5||19.1||17.8||14.5||2.5||1.5||1.5|
(i) Name the rainiest month of the year. What is the reading?
(ii) How annual range of temperature is calculated?
(iii) Which two months have the least rainfall?
Ans. (i) The rainiest month of the year is July. It receives 19.1 mm rainfall.
(ii) Annual range of temperature is calculated by using formula :
|Equable Climate||Continental Climate|
|(1) Area which are neither too warm in summers nor too cold in winters (with low range of temperature) are said to have an equable climate.||Places with higher range of temperature (extremes of temperature) experience extreme climate, it is known as continental climate.|
|(2) Equable climate is characterized by well distributed rainfall throughout the year.||Rainfall in extreme climate is restricted to summer months.|
|(3) This type of climate is found in places located close to the sea having the moderating influence of the sea.||Interiors of continents/countries which have the least influence of the sea experience this type of climate.|
|(4) Chennai, Kochi, Mumbai, etc.||Delhi, Kanpur, Bhopal, etc.|
Q. Why is the monsoon considered a unifying bond?
Ans. The unifying influence of the monsoon on the Indian subcontinent is quite perceptible.
(i) The seasonal alteration of the wind systems and the associated weather conditions provide a rhythmic cycle of seasons. Even the uncertainties of rain and uneven distribution are very much typical of the monsoons.
(ii) The Indian landscape, its animal and plant life, its entire agricultural calendar and the life of the people (including their festivities) revolve around this phenomenon.
(iii) Year after year, people of India from north to south and from east to west, eagerly await the arrival of the monsoon.
(iv) These monsoon winds bind the whole country by providing water to set the agricultural activities in motion.
(v) The river valleys which carry this water also unite as a single river valley unit.
(vi) There are cultural celebrations linked with the arrival of monsoon throughout the country.
Q. Assertion (A) : Climate refers to the sum total of weather conditions and variations over a large area for a long period of time.
Reason (R) : It keeps on changing with the direction of winds.
Ans. (c) A is correct but R is wrong.
Assertion is correct because climate refers to the sum total of weather conditions and variations over a large area for a long period of time (more than thirty years). But the reason given doesn’t support the assertion and it is wrong statement also. As it doesn’t change with the wind direction. It include various elements like- temperature, atmospheric pressure, wind, humidity and precipitation. So, A is correct and R is wrong.
Q. The wind blowing in the Northern Plains in summers is known as :
(a) Kaal Baisakhi
(c) Trade winds
(d) None of these
Q. Which one of the following causes rainfall during winters in north-western part of India.
(a) Cyclonic depressions
(c) Western disturbances
(b) Retreating monsoon
(d) Southwest monsoon