Updated by Tiwari Academy
on June 12, 2023, 8:34 AM
Class 8 Science Chapter 8 MCQ (Multiple Choice Questions) of Force and Pressure for CBSE and State boards like UP board, MP board and other board who are following NCERT books for session 2024-25. All the questions are taken from latest NCERT books issued for new academic session. Practice with these questions to clear all of your doubts and to be confident in exams. Class 8 science chapter 8 MCQs covers the entire chapter and all the topics with suitable answers and explanation.
Class 8 Science Chapter 8 MCQ
Class: 8
Science
Chapter: 8
Force and Pressure
Contents:
MCQ Online Test with answers
Session:
2024-25
MCQ Tests with Answers for Class 8 Science Chapter 8
Q1
Which of the following is not an example of muscular force?
[A]. A porter carrying a load on a wheel-barrow.
[B]. An apple falling from a tree.
[C]. A child riding a bicycle.
[D]. A person drawing water from a well.
Answer: Option B
Explanation:
All are the examples of muscular force except one. An apple falling from a tree is example of gravitational force. The force with which the earth pulls the objects towards it, is called the force of gravity. Gravity is a natural force of attraction or pull.
Two boys A (left side) and B (right side) are applying force on a block. If the block moves towards the right, which one of the following statements is correct?
[A]. Magnitude of force applied by A is greater than that of B.
[B]. Magnitude of force applied by A is smaller than that of B.
[C]. Net force on the block is towards A.
[D]. Magnitude of force applied by A is equal to that of B.
Answer: Option A
Explanation:
Magnitude of force applied by A is greater than that of B because the block moves towards right i.e., towards B.
In the electric bell circuit, when the circuit is completed, the hammer strikes the gong. Which of the following force is responsible for the movement of hammer?
[A]. Gravitational force alone
[B]. Electrostatic force alone
[C]. Magnetic force alone
[D]. Frictional force alone
Answer: Option C
Explanation:
It will be magnetic force because as electric current flows through the coil, it behaves like electromagnet and magnetic force is created.
When we press the bulb of a dropper with its nozzle kept in water air in the dropper is seen to escape in the form of bubbles. Once we release the pressure on the bulb, water gets filled in the dropper. The rise of water in the dropper is due to:
[A]. Pressure of water
[B]. Gravity of the earth
[C]. Shape of rubber bulb
[D]. Atmospheric pressure
Answer: Option D
Explanation:
A dropper works on the existence of atmospheric pressure. When we press the rubber bulb of the dropper by keeping its nozzle dipped in water or liquid, the air present in the glass tube and bulb is seen to escape in the form of bubbles. Due to this, the air pressure inside the glass tube and rubber bulb of dropper is very much reduced. When we now released the rubber bulb of dropper, the much greater atmospheric pressure acting on the surface of liquid, pushes the liquid up into the dropper tube.
If we release a magnet held in our hand, it falls to the ground. The force responsible for this is:
[A]. Muscular force
[B]. Magnetic force
[C]. Electrostatic force
[D]. Gravitational force
Answer: Option D
Explanation:
The force with which the earth pulls the objects towards it, is called the force of gravity. Gravity is a natural force of attraction or pull.
If we drop a stone from some height, it falls down towards the earth. A leaf falls from the tree due to gravity. Rain falls down to earth due to the force of gravity. When we open a tap, water begins to flow down towards the ground due to the force of gravity. There are so many examples of gravitational force.
Which of the following force is utilized in reducing air pollution by removing dust, soot and fly-ash particles from the smoke coming out of chimneys of factories?
[A]. Magnetic force
[B]. Gravitational force
[C]. Electrostatic force
[D]. Frictional force
Answer: Option D
Explanation:
An electrostatic precipitator is a type of filter (dry scrubber) that uses static electricity to remove soot and ash from exhaust fumes before they exit the smokestacks. This one common air pollution control device. Most power stations burn fossil fuels such as coal or oil to generate electricity for use.
Which of the following represent correct values for the normal atmospheric pressure?
[A]. 101.3 kilopascals and 76 mm of mercury
[B]. 76 mm of mercury and 101.3 pascals
[C]. 101.3 kilopascals and 76 cm of mercury
[D]. 76 mm of mercury and 76 cm of mercury
Answer: Option C
Explanation:
Atmospheric pressure is the pressure exerted by the atmosphere, or rather the weight of air above a point on Earth. It can be measured using a barometer. The unit of pressure is Pascals. As we go to a higher altitude on Earth, the weight of air above it decreases, so the pressure will also be lesser. So atmospheric pressure decreases with increasing elevation.
Atmospheric pressure is measured using a barometer. At sea level, the barometer will read a value of standard or normal atmospheric pressure, equivalent to the pressure exerted by 760 mm or 76 cm, tall column of mercury or 101.3 kilopascals. Hence, your answer will be option [C].
Which of the following does not work on the existence of atmospheric pressure?
[A]. Rise of iodine solution in the glass tube of dropper
[B]. Rise of cold drink in a long plastic straw
[C]. Sticking of suction hook on the wall of a room
[D]. Rise of mercury in glass tube of thermometer
Answer: Option D
Explanation:
The rise in the level of mercury in glass tube of thermometer will not work due to the presence of atmospheric pressure. A thermometer works on the principle that mercury expands with increase in temperature. So, the mercury in a glass tube of thermometer will rise only due to increase in temperature.
Which of the following change appreciably when a batsman hits a moving cricket ball?
[A]. Shape and Direction
[B]. Direction and Size
[C]. Shape and Size
[D]. Direction and Speed
Answer: Option D
Explanation:
A force can change the speed of a moving object. A force can change the direction of a moving object. A force can change the composition of a moving object. A force can change the shape and size of an object. But when a batsman hits a moving cricket ball, its direction and speed changed, not shape and size. Hence, your answer will be option [D].
[A]. A force can change the speed of a moving object
[B]. A force can change the direction of a moving object
[C]. A force can change the composition of a moving object
[D]. A force can change the shape and size of an object
Answer: Option C
Explanation:
A force can change the speed of a moving object. A force can change the direction of a moving object. A force can change the composition of a moving object. A force can change the shape and size of an object. But force cannot change the composition of a moving object or any object. Though composition is a chemical change.
Which of the following is not a non-contact force?
[A]. Electrostatic force
[B]. Gravitational force
[C]. Frictional force
[D]. Magnetic force
Answer: Option C
Explanation:
A force which can be exerted by an object on another object only through “physical touching” is called a contact force. Such as:
i)Muscular force and
ii)Friction force
These are example of contact forces, but a force which can be exerted by an object on another object even from a distance (without touching) is called a non-contact force. Such as,
i)Magnetic force
ii)Electrostatic force and
iii)Gravitational force
The force of 150 N is applied to an object of area 3 m2. Calculate the pressure.
[A]. 25 N/m2
[B]. 50 N/m2
[C]. 100 N/m2
[D]. 147 N/m2
Answer: Option B
Explanation:
Force = 100 N, Area = 3 m2
Putting these values in the formula for pressure:
Pressure = 100 N/2 m2
= 50 N/m2
Thus, the pressure is 50 newtons per square meter or 50 pascals.
In a science quiz competition, Payel is asked a question where she had to choose the statement which was/were incorrect?
[A]. The greater the depth of a point in a liquid, the greater is the pressure.
[B]. A liquid exerts pressure on the walls of its container.
[C]. The atmospheric pressure is maximum at the high mountain.
[D]. None of the above.
Answer: Option C
Explanation:
On the surface of earth, the atmospheric pressure is maximum at the sea level, because the column of air above us is tallest at the sea level. The atmospheric pressure on the surface of earth (at the sea-level) is 101.3 kilopascals, which is equivalent to the weight of 10 elephants pressing on each square metre area. As we go up in the atmosphere from the surface of earth, the atmospheric pressure goes on decreasing.
A pressure of 10 kPa acts on an area of 0.3 m2. The force acting on the area will be:
[A]. [A] 3000 N
[B]. 30 N
[C]. 3 N
[D]. 300 N
Answer: Option A
Explanation:
We can calculate pressure using the formula,
Pressure = Force / Area.
In this case, pressure = 10 kPa = 10 x 1000 = 10000 Pa and area = 0.3 m2. So, we can find force as follows:
Force = Pressure x area = 10000 x 0.3 = 3000 Newtons.
So, a force of 3000 N is required to create a pressure of 10 kPa for an object of area 0.3 m2.
The magnitude of atmospheric pressure is equal to the pressure exerted by a:
[A]. 76 mm tall column of mercury
[B]. 760 mm tall column of alcohol
[C]. 76 cm tall column of mercury
[D]. 760 cm tall column of mercury
Answer: Option C
Explanation:
We know that the SI unit of pressure is pascal (Pa) but atmospheric pressure is usually measured in the unit of “millimeter of mercury” (mm of mercury) for the sake of convenience in measuring it. The atmospheric pressure on the surface of earth (at the sea level) is 760 mm of mercury.
The atmospheric pressure is usually measured in the unit of:
[A]. Newtons per square meter
[B]. Pascal
[C]. Cm of mercury
[D]. Mm of mercury
Answer: Option D
Explanation:
The SI unit of pressure is pascal (Pa) but atmospheric pressure is usually measured in the unit of “millimeter of mercury” (mm of mercury) for the sake of convenience in measuring it.
When a force of 5 N acts on a surface, it produces a pressure of 500 Pa. The area of surface then must be
[A]. 10 cm2
[B]. 50 cm2
[C]. 100 cm2
[D]. 0.01 cm 2
Answer: Option C
Explanation:
The pressure depends on two factors: a) Force applied and b) Area over which force acts.
Pressure = Force / Area
Area = Pressure / Force
= 500/ 5
= 100 cm2
When we press the rubber sucker on a flat, smooth surface. A rubber sucker stays attached firmly to a flat surface due to:
[A]. Gravity of the earth inside
[B]. Low atmospheric pressure inside
[C]. High atmospheric pressure inside
[D]. High electrostatic force creates inside
Answer: Option B
Explanation:
When we press the rubber sucker on a flat, smooth surface, its concave rubber cup gets flattened to a large extent, pushing out most of the air from beneath it. Since, very little air remains inside the flattened rubber sucker, therefore, the air pressure inside the rubber sucker becomes very low (and a partial vacuum is created). The much greater atmospheric pressure acting on the rubber sucker from outside fixes the rubber sucker firmly on the flat surface.
Just read the complete chapter from NCERT Textbook and go through the exercise questions answers given at the end of the chapter of NCERT book. Now work on important questions and MCQ questions to learn thoroughly the entire chapter 8 of class 8 Science.