Free Our Environment 02 Practice Test - 4th Grade
Question 1
_______ is the imaginary line that passes through the centre of the Earth.
String
Axis
Golden Line
Equator
SOLUTION
Solution : D
Equator is the imaginary line that passes through the centre of the Earth, dividing it into northern and southern hemispheres.
Question 2
Which of the following is the main source of carbon monoxide
Plants
Automobiles
Oceans
Household waste
SOLUTION
Solution : B
Carbon monoxide is a poisonous gas. The incomplete combustion of carbon-containing fuels, such as gasoline, natural gas, oil, coal, and wood leads to the formation of it. Out of the given options, automobiles are the source of carbon monoxide production.
Question 3
Incomplete burning of fuel produces _______which is a poisonous gas.
Oxygen
Nitrogen
Carbon monoxide
Hydrogen
SOLUTION
Solution : C
Incomplete burning of fuel leads to the formation of carbon monoxide which is a poisonous gas. Carbon monoxide gas, when inhaled, combines with blood and reduces its oxygen carrying capacity thereby damaging the nervous system and even results in death.
Question 4
Choose the correct season in which leaves turn pale and start to shed from the trees.
Autumn
Winter
Summer
Spring
SOLUTION
Solution : A
Autumn is one of the seasons in which the leaves of trees and plants turn pale. It is the transition between the summer and the winter seasons. In this season, the temperature gradually falls down and trees are seen shedding their leaves and flowers.
Question 5
Which layer of the atmosphere has ozone layer in it?
Troposphere
Stratosphere
Mesosphere
Thermosphere
SOLUTION
Solution : B
About 90% of ozone is present in the stratosphere. It is between 10 and 17 kilometers above the Earth's surface and extends up to 50 kilometers. This layer protects the Earth from the harmful UV rays.
Question 6
Which of the following phenomenon occurs during daytime?
Land breeze
Warm breeze
Cold breeze
Sea breeze
SOLUTION
Solution : D
During the day time, land gets heated faster than water. The hot air above land is replaced with cold air from sea. This phenomenon is known as sea breeze.
Question 7
Water pollution is:
contamination of water bodies
purification of drinking water
process of adding minerals to the water that is essential for living
adding salts to water
SOLUTION
Solution : A
Water pollution is the contamination of water bodies (e.g. lakes, rivers, oceans, aquifers and groundwater). Harmful substances such as sewage, toxic chemicals, silt, etc. gets mixed with water, thereby polluting it.
Question 8
Increase in amount of carbon dioxide in air results in:
Global warming
Global radiation
Global pressurization
SOLUTION
Solution : B
Increase in amount of carbon dioxide in air results in global warming and greenhouse effect.
Most of the radiations that Earth receives by the Sun is reflected back. Earth gets heated up by these reflected radiations and this heat is trapped by the atmosphere. This phenomenon is called green house effect and due to this heating there is an increase in the average temperature of the Earth's atmosphere. This is called global warming.
Question 9
Which of the following are greenhouse gases?
Nitrogen
Oxygen
Carbon dioxide
Hydrogen
SOLUTION
Solution : C
Greenhouse gases are the gases in the atmosphere that are capable of absorbing the infrared radiations from the earth, thereby trapping the heat in the atmosphere. This trapped heat is increasing the global temperature leading to global warming and this phenomenon is known as the greenhouse effect. Examples of greenhouse gases are methane, water vapour, carbon dioxide.
Question 10
Which of the following images is that of a desert?
SOLUTION
Solution : A
Deserts are large dry areas which have very little vegetation. They are usually covered with sand.
The below given image is that of a desert.
