Chapter 6 Primary Concept Of Force And Energy Review Questions Environment Review Questions MCQs
Question 1. SI unit of force is
- Dyne
- Kg
- Newton
- None of these
Answer: 3. Newton
Question 2. Magnet attracts
- Iron nails
- Eraser
- A plastic scale
- Wooden pencil
Answer: 1. Iron nails
Read And Learn More: WBBSE Solutions For Class 6 School Science
Question 3. Force can change a body.
- Mass
- Weight
- Density
- Shape
Answer: 4. Shape
Question 4. SI unit of weight is
- Gram
- Dyne
- Density
- Shape
Answer: 4. Shape
WBBSE Class 6 Force and Energy MCQs
Question 5. An object that has kinetic energy must be
- Lifted above the earth’s surface
- In motion
- At rest
- None of the above
Answer: 2. In Motion
Question 6. As height increases, so does
- Thermal energy
- Chemical energy
- Atomic energy
- Potential energy
Answer: 4. Potential energy
Question 7. _________ is a non-magnetic substance.
- Wood
- Cobalt
- kg
- Newton
Answer: 1. Wood
Question 8. Which is the major advantage of using sources such as sunlight, wind, and running water instead of fossil fuels, such as coal and natural gas?
- Sunlight, wind, and running water are much more efficient than fossil fuels
- Sunlight, wind, and running water are renewable and available indefinitely
- Sunlight, wind, and running water are much less expensive to use than fossil fuels
- Sunlight, wind, and running water can be used at any geographical location
Answer: 2. Sunlight, wind, and running water are renewable and available indefinitely
Question 9. When a boat sail forward, it uses
- The frictional force of air
- The potential energy of air
- The kinetic energy of air
- The chemical energy of air
Answer: 4. Chemical energy of air
Question 10. Man is ___________ but cow is
- Herbivore, omnivore
- Omnivore, herbivore
- Carnivore, herbivore
- Omnivore, carnivore
Answer: 2. Omnivore, herbivore
Understanding Force and Energy Concepts
Question 11. If a football is rolled on the field, it stops after traveling through a certain distance. The responsible factor for this incident is
- Mass of the ball
- The shape of the ball
- Force of friction
- Force of gravity
Answer: 3. Force of friction
Question 12. Which of the following food chain is not correct?
- Grass Grasshopper→→Toad→Snake Mongoose
- Leaf of plant→→→Locust→→Myna
- Leaf of plant->Rabbit->Hawk T2300
- Grass Dear→Giraffe
Answer: 4. Grass Dear→Giraffe
Question 13. The food you eat and fossil fuels are both examples of this form of energy.
- Atomic energy
- Thermal energy
- Chemical energy
- Mechanical energy
Answer: 3. Chemical energy
Practice MCQs on Newton’s Laws of Motion
Question 14. What device among the following converts chemical energy to mechanical energy?
- Human
- Car
- Jetski
- All of these
Answer: 4. All of these
Question 15. Which of the following is the best example of increasing an object’s potential energy?
- Rolling a bowling ball
- Turning on a light bulb
- Dropping a light bulb
- Stretching a rubber band
Answer: 4. Stretching a rubber band
Question 16. Which one is a primary consumer?
- Grass
- Goat
- Tiger
- Vulture
Answer: 2. Goat
Question 17. Energy flow in an ecosystem is
- Unidirectional
- Bidirectional
- Multidirectional
- Reversible
Answer: 1. Unidirectional
Common MCQs on Types of Forces
Question 18. On which surface will a toy sled travel the furthest?
- Rock
- Carpet
- Polished wood
- Ice
Answer: 4. Ice
Question 19. Energy transfer from one trophic level to another in a food chain is
- 1%
- 10%
- 2%
- 20%
Answer: 2. 10%
Question 20. Potential energy is
- Stopped energy
- Thermal energy
- Stored energy
- Moving energy
Answer: 3. Stored energy
Question 21. All forms of energy which are available on earth have their origin from
- The chlorophyll
- The sun
- The nuclear fission
- The tides
Answer: 2. The sun
Question 22. The beating of a drum with sticks produces ___________ from ___________
- Sound energy, mechanical energy
- Mechanical energy, sound energy
- Sound energy, electrical energy
- Sound energy, heat energy
Answer: 1. Sound energy, mechanical energy
Question 23. Magnetic attraction is a type of
- Frictional force
- Gravitational force
- Contact force
- Non-contact force
Answer: 4. Non-contact force
Class 6 WBBSE Science Question Answer
Question 24. In an ecosystem, if there are 40,000 kg of producers, how many kg of tertiary consumers are there?
- 4 kg
- 40 kg
- 400 kg
- 4000 kg
Answer: 2. 40 kg
Question 25. What type of energy is produced at the time of clapping?
- Sound energy
- Chemical energy
- Magnetic energy
- All of these
Answer: 1. Sound energy
Question 26. Between two balls weighing 10 kg and 20 kg, which one would experience more friction?
- 10 kg ball
- 20 kg ball
- Same for both
- None of the above
Answer: 2. 20 kg ball
Question 27. Kicking a football is
- Pull
- Push
- Impulse
- Throw
Answer: 3. Impulse
Question 28. An example of a renewable source of energy is
- Coal
- Natural gas
- Petroleum
- Tidal energy
Answer: 4. Tidal energy
Question 29. Blowing of electric horn involves the transformation of
Short MCQs on Work, Power, and Energy
- Mechanical energy to sound energy
- The heat energy to sound energy
- Electrical energy to sound energy
- Chemical energy to sound energy
Answer: 3. Electrical energy to sound energy
Question 30. An example of force without touch is
- Nuclear force
- Magnetic attraction
- electrostatic repulsion
- all of these
Answer: 4. All of these
Chapter 6 Primary Concept Of Force And Energy Fill In The Blanks
Question 1. Cobalt and magnet __________ each other.
Answer: Attract
Question 2. Coal, petroleum, and natural gases are known as __________ energy.
Answer: Non-renewable
Question 3. The gravitational force acting on a body is called it’s __________
Answer: Weight
Question 4. While closing the zip of your school bag, you apply __________ force.
Answer: Pulling
Question 5 The smoother the surface, the less the __________
Answer: Friction
Question 6. Energy flow in the ecosystem is __________
Answer: Unidirectional
Question 7. Interconnected food chains are called __________ __________.
Answer: Food web
Question 8. Only __________ % of energy is taken at each trophic level of the energy pyramid.
Answer: 10
Class 6 WBBSE Science Question Answer
Question 9. Complete the food chain Paddy Rat→ __________ →Hawk.
Answer: Snake
Question 10. The object which changes its position with respect to time is called a ______________object.
Answer: Moving
Question 11. The capacity of a body to do work is called __________.
Answer: Energy
Question 12. __________ and __________ energy are forms of mechanical energy.
Answer: Potential, Kinetic
Question 13. __________ converts solar energy into electrical energy.
Answer: Solar Photovoltaic Cells
Question 14. During photosynthesis, __________ energy is transformed into energy.
Answer: Light, Chemical
Question 15. The lowest trophic level of the food pyramid is composed of __________
Answer: Producers
Chapter 6 Primary Concept Of Force And Energy Identify As True Or False
Question 1. Aluminum and copper are magnetic substances.
Answer: False
Question 2. Friction acts in the same direction as the impressed force which causes motion.
Answer: False
Question 3. Wind and tidal energy are renewable sources of energy.
Answer: True
Question 4. In the Sl system, a unit of force is done.
Answer: False
WBBSE Class 6 Science Question Answer
Question 5. Friction is associated with disadvantages only.
Answer: False
Question 6. Most forms of energy can be converted into other forms of energy.
Answer: True
Question 7. Green plants belong to the tertiary trophic level of the food chain.
Answer: False
Question 8. Running water produces hydel energy.
Answer: True
Question 9. The description of motion is independent of the location of the viewer.
Answer: False
Question 10. Push can act through the non-rigid connector.
Answer: False
Question 11. There are 8 forms of energy prevalent in nature.
Answer: True
Question 12. Push and pull are contact forces.
Answer: True
Question 13. The apex of the food pyramid involves more energy than the base.
Answer: False
Question 14. Wood is a type of non-renewable source of energy.
Answer: True
Chapter 6 Primary Concept Of Force And Energy Match The Columns
Question 1.
Answer: A-1,B-3,C-4,D-2
Question 2.
Answer: A-4,B-1,C-2,D-3
Question 3.
Answer: A-3,B-4,C-2,D-1
Question 4.
Answer: A-5,B-1,C-2,D-4
Chapter 6 Primary Concept Of Force And Energy Answer In Words Or A Sentence
Question 1. What % of energy is absorbed in each trophic level?
Answer: 10% energy.
Question 2. Does friction depend on the area of the surface in contact with each other?
Answer: No.
Question 3. How is each food level in a food pyramid known?
Answer: Trophic level.
WBBSE Class 6 Science Question Answer
Question 4. Who formulated the concept of the 10 percent law?
Answer: Raymond Lindemann.
Question 5. What is the unit of weight in the CGS system?
Answer: Dyne.
Question 6. Which one is more stable-food chain or the food web?
Answer: Food web.
Question 7. Give an example where chemical energy is transformed into heat, light, and sound energy.
Answer: Bursting of cracker.
Question 8. Give two examples of fossil fuels.
Answer: Coal and petroleum.
Question 9. What type of force is involved while we take out a drawer?
Answer: Pull.
Question 10. What do the animals which live on plants known as?
Answer: Herbivores.
Question 11. Choose the odd one out-tiger, dog, cow, leopard.
Answer: Cow (herbivores); others are carnivores.
Question 12. Sort out the magnetic substance-wood, plastic, kerosene, cobalt.
Answer: Cobalt.
Question 13 Mention two devices that convert solar energy.
Answer: Solar cooker and solar lantern.
Question 14. What is the SI unit of friction?
Answer: The SI unit of friction is Newton.
Question 15. State the type of energy transfer that occurs when window panes break due to an explosion.
Answer: Chemical energy to mechanical energy.
Question 16. State the type of energy transfer that occurs when we hear a radio broadcast of a cricket match.
Answer: Electrical energy to sound energy
Question 17. Which organisms come last in each trophic level?
Answer: Detrivores and decomposers (ex: Dung beetles, fungi, bacteria, etc.)
Question 18. Which trophic level consists of the greatest number of organisms?
Answer: First trophic level or Producers.
Question 19. What is the force that is responsible for wearing out of bicycle tires?
Answer: Frictional force of road.
Question 20. What is the direction of the force of friction acting on a moving object?
Answer: Opposite to the direction of motion.
Chapter 6 Primary Concept Of Force And Energy Short Answer Type Questions
Question 1. Arrange in order: rain, water, cloud, vapor.
Answer: Water vapour→ cloud→rain.
Question 2. Give an example where the force of friction is advantageous to us and explain it.
Answer: Friction helps us in walking. When a man walks, he lifts one leg up, leans forward, and with the other leg presses the ground in a slightly inclined fashion in the backward direction.
The pressing of the leg is balanced by the frictional force of the ground, otherwise, he will slip and fall forward on his face. Thus friction prevents him from slipping.
Examples of Real-Life Applications of Force
Question 3. Current is drawn from the following devices(a) a Generator and (b) A dry cell. State the energy transformation taking place in each case.
Answer:
- In a generator, mechanical energy changes into electrical energy.
- A dry cell converts the stored chemical energy into electrical energy.
Question 4. How do contact forces act?
Answer: Contact forces are to be applied through something rigid or non-rigid. Push is applied through something rigid while a pull can act through a non-rigid connector, such as a rope or a wire.
Question 5. What is mechanical energy?
Answer: Kinetic and potential energies are together known as mechanical energy. It is the energy associated with the motion and position of an object.
Question 6. What is the water cycle?
Answer: The water cycle is the cycle of processes by which water circulates between the earth’s water bodies, atmosphere, and land involving evaporation, transpiration, condensation, and precipitation.
Question 7. What are the causes of the energy crisis?
Answer: The causes of the energy crisis may be briefly summarised as
- Increase in population and rapid urbanization leading to overconsumption
- Increase in automobiles
- Growing needs of industries and mechanized agriculture.
- The decline of stored fossil fuels.
- Poor infrastructure, flaws in the distribution network, and wastage
- Miscellaneous factors like war, natural calamities, etc
Question 8. What are magnetic substances?
Answer: Materials that can be magnetized and which are strongly attracted to a magnet are called magnetic substances. These include iron, cobalt, lodestone, etc.
Question 9. Arrange the following organisms in the correct sequence from producer to secondary consumer
Kingfisher-algae-fish.
Answer: The correct sequence shall be-
algae (producer) fish (primary consumer) → kingfisher (secondary consumer).
Question 10. Suppose you are traveling in a bus or train. When the bus or train is in motion, which objects would appear to be at rest to you?
Answer: When an observer is inside a moving train, then the compartment itself along with its fixed components (such as berths, seats, window frames, etc.) and the passengers who are seated inside the compartment shall appear stationary to the observer.
Question 11. Name a force that causes the dissipation of energy. On what factors does this force depend?
Answer: Friction causes the dissipation of energy in the form of heat.
The factors on which friction depends are:
- Friction depends on the material and the nature of the surfaces in contact and their state of polish.
- Friction depends upon the mass of the body because that in turn determines how the surfaces in contact are pressed together.
Conceptual Questions on Mechanical Advantage
Question 12. Friction is independent of area. But brakes of very small contact areas are not used. Why?
Answer: It is true that friction does not depend on the area of contact but it causes a lot of wear and tear.
WBBSE Class 6 Science Question Answer
Thus brakes have to be built with appreciable contact areas to avoid wear and tear and to increase the life span of the brake shoe or pad.
Chapter 6 Primary Concept Of Force And Energy Long Answer Type Questions
Question 1. Define force. What is its unit in the Sl system? State any two effects of force.
Answer: A force may be defined as an external cause that changes or tends to change the state of rest or of the uniform motion of a body in a straight line.
In the Sl system, the unit of force is called Newton. Two effects of force are
1. It can set a stationary body into motion.
A railway engine can move a stationary train by applying a pull or push.
2. It can stop a moving body.
A speeding car is stopped by the application of brakes.
Question 2. ‘Sun is the ultimate source of all energies available on earth’ discuss.
Answer: When a man walks, he lifts one leg up, leans forward, and with the other leg presses the ground in a slightly inclined fashion in the backward direction.
Question 3. What is a pyramid of energy? Why is there the highest amount of energy at the base and the lowest at the apex of an energy pyramid?
Answer: The Push is applied through something rigid while a pull can act through a non-rigid connector, such as a rope or a wire.
Question 4. What is friction? Give examples (one each) of the following
1. friction produces heat
2. friction causes wear and tear of mating surfaces.
Answer:
1. Friction produces heat:
- When two palms are rubbed together, they become warm.
- If a stone is rubbed on a metallic surface for some time, the metal becomes hot.
- When we want to ignite a matchstick, we rub the stick on the rough surface of a matchbox.
The rough surface of the matchbox and the head of the matchstick both contain gunpowder on them. Rubbing causes the temperature to increase and heat is produced which ignites the matchstick.
2. Friction causes erosion of contact surfaces:
1. The tires of cars or cycles get eroded after a long run.
Real-Life Scenarios Involving Friction and Gravity
Question 5. State the differences between renewable and non-renewable sources of energy.
Answer:
Question 6. Explain the 10 percent law in connection with the energy pyramid.
Draw a food chain with respect to energy flow in a commonly formed ecosystem formed of the organisms named below
(1) Hawk (2) Grasshopper (3) Grass (4) Snake (5) Toad.
Answer: According to the 10 percent law, about 10% of total energy is transmitted during energy flow through several trophic levels to be used up for building the body mass, and rest is dissipated as heat energy.
For example, 100 kg biomass in the grass will make 10 kg biomass for herbivorous animals (ex. deer) and 1 kg Primary Concept of Force and Energy Grass Grasshopper→Toad Snake→Hawk.
Question 7. When a ball is thrown vertically upward, how do its potential and kinetic energy change?
Answer: At the moment when the ball is thrown, it has only kinetic energy due to an upward velocity. As it attains height, it loses kinetic energy because its velocity decreases and gains potential energy.
WBBSE Class 6 Science Question Answer
At the highest point of ascent, the ball stops momentarily possessing potential energy only. During descent, it loses potential energy and gains kinetic energy as its velocity increases with time.
Just before touching the ground, the ball possesses kinetic energy only.
Question 8. A solar cooker is turned ON. Which type of energy conversion is taking place here? Name two possible measures to mitigate the global energy crisis.
Answer: When a solar cooker is turned ON, light energy is converted into heat energy.
Two steps to mitigate the global energy crisis:
1. Higher utilization of renewable types of energy in a planned manner.
2. Prevention of wastage of energy in daily urban life.
Question 9. How does the transfer of energy take place in the water cycle?
Answer: Solar energy causes surface water to undergo evaporation to become water vapor. As the water vapor attains height it gains potential energy.
Once water vapor is in the upper part of the atmosphere, it releases heat to the surrounding colder air to either condense into liquid or form ice crystals.
Air currents move the clouds across the planet. The water droplets in clouds collide with other droplets to form larger droplets and undergo precipitation as rain or snowfall under the influence of gravity.
As it falls it gains kinetic energy. Kinetic energy drives runoff water that flows downhill through streams, rivers, and lakes.
Some of the water eventually reaches the oceans and again participates in the water cycle.
Thus it is self-renewing and continuous and the sun provides all the energy to cause the change of states through the processes of melting, sublimation, evaporation, freezing, condensation, and deposition.