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CBSE class 9 Science Quiz | CBSE class 9 Science Multiple Choice Questions(MCQs) & Answers

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Questions
1 According to the law of conservation of energy,
A The total energy before and after the transformation always remains constant
B Energy can only be transformed from one form to another
C It can neither be created nor destroyed
D All of the above

Answer: All of the above
2 For an object of mass 'm', falling freely from height 'h', under acceleration due to gravity 'g', If v is the velocity of the object at a given instant, then during the course of its fall, for all points, which of the expression given below is correct ?
A mgh > 1/2 mv2
B mgh < 1/2 mv2
C mgh = 1/2 mv2
D mgh + 1/2 mv2 = Constant

Answer: mgh + 1/2 mv2 = Constant
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3 In Force vs Displacement graph, What does the area under the curve represents :
A Work done
B Force
C Acceleration
D Velocity

Answer: Work done
4 A vector quantity has both magnitude as well as direction, where as a scalar quantity has only magnitude and no direction. which of the given below is a scalar quantity?
A Velocity
B Force
C Work done
D Momentum

Answer: Ingredients
5 Which of the following is correct?
A A piston with compressed air contains potential energy
B A fruit hanging from the tree possesses gravitational potential energy
C A running player acquires Kinetic Energy
D All of the above

Answer: All of the above
6 A body is moving with velocity 4 m/s , possesses 56 Joules of Kinetic Energy. The momentum of body will be equal to
A 28 kgms-1
B 21 kgms-1
C 7 kgms-1
D 14 kgms-1

Answer: 28 kgms-1
7 In a construction site, a crane lifts 1000 kg of concrete mix to roof top at a height of 20 meters in 50 seconds. If the value of gravity 'g' due to earth is 10 m s-2, the power of elevator will be..
A 4 KW
B 5 KW
C 2 KW
D None of these

Answer: 4 KW
8 An object is thrown vertically upward and it reaches to a maximum height 'h' from the ground. During its flight, on reaching 3/4 of height H, it will acquire?
A more potential and less kinetic energy
B same potential and kinetic energy
C less potential and high kinetic energy
D only kinetic energy

Answer: more potential and less kinetic energy
9 An object is subjected to free fall from height 'h' to ground. At mid point of its fall i.e. at 1/2 of height H, it will acquire?
A same kinetic and potential energy
B less kinetic and more potential energy
C more kinetic and less potential energy
D only potential energy

Answer: same kinetic and potential energy
10 An object is displaced by 10 meters in the direction of applied force. If the applied force is 75 N, What is the work done by the force?
A 750 joule
B 75 joule
C 0.75 Joule
D None of these

Answer: 750 joule
11 According to the law of conservation of energy, which of the statements given below is correct ?
A Energy can not be transformed from one form to another
B It can be created or destroyed.
C The total energy before and after the transformation always remains constant.
D The total energy before and after the transformation is always different.

Answer: The total energy before and after the transformation always remains constant.
12 When a body slides down on an inclined surface, which holds true ?
A It has both kinetic and potential energy
B It has kinetic energy only
C It has no energy
D It has potential energy only

Answer: It has both kinetic and potential energy
13 In hydro electricity generation, water stored in a dam possesses:
A potential energy
B thermal energy
C electrical energy
D chemical energy

Answer: potential energy
14 When a body falls freely towards the earth then the total energy
A remains constant
B increases
C decreases
D first increases and then decreases

Answer: remains constant
15 Expression for Power of an object is equal to:
A Power = Work done/Time
B Power = Force X Displacement
C Power = Work done X Time
D Power = Time/ Work done

Answer: Power = Work done/Time
16 When we stretch a rubber band, the Elastic Potential Energy of rubber band
A remains unchanged
B becomes zero
C increases
D decreases

Answer: increases
17 The person will have maximum Potential Energy, when ?
A he is standing on the roof
B he is sleeping on the bed
C he is sleeping on the ground
D he is sitting on the ground

Answer: he is standing on the roof
18 A cyclist is moving at a speed of 5 m/s on leveled road. While going down the slop, his speed increases to 7 m/s. Here the nature of work done by gravitational force in increasing the speed of cyclist is an example of ?
A positive work done
B negative work done
C Infinite work done
D Zero work done

Answer: positive work done
19 In first case, a force of 5 N is applied on a object for 6 minutes and displaces it by 10 meters. In second case, A force of 10 N is applied on the same object for 3 minutes and displaces it by 5 meters. In which case there is more work done?
A First case
B Second case
C In both cases, work done is same
D In both cases, work done is zero

Answer: In both cases, work done is same
20 As per the statement of Q.9, the amount of addition work done by the car, after applying the accelerator, is
A 4 Mv2
B 3.5 Mv2
C 1.5 Mv2
D 2.5 Mv2

Answer: 4 Mv2
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