CBSE Questions for Class 9 Physics Work And Energy Quiz 1 - MCQExams.com

What is the unit of energy in food ?
  • $$Kilo$$ $$calorie$$
  • $$Erg$$
  • $$Joule$$
  • $$Calorie$$
The form of energy present in a wound spring is:
  • chemical
  • heat energy
  • magnetic
  • mechanical
Asha lifts a doll from the floor and places it on a table. If the weight of the doll is known, what else does one need to know in order to calculate the work Asha has done on the doll?
  • The time required
  • Height of the table
  • Mass of the doll
  • Cost of the doll
When the force retards the motion of a body, the work done is:
  • Zero
  • Negative
  • Positive
  • Positive or negative depending upon the magnitude of force and displacement
1 $$hp$$ is equal to:
  • $$0.746kW$$
  • $$7.46 kW$$
  • $$74.6kW$$
  • $$746 kW$$
The total energy at the start of the free-fall of an object is?
  • Zero
  • Infinite
  • $$mgh$$
  • None of these
As an object falls, its ______ energy changes into ______ energy.
  • Kinetic, Potential
  • Potential, Kinetic
  • Total, Potential
  • Kinetic, Total
A boy held a book of 1 kg at a height of 1 metre for 60 seconds. Calculate the work done :
  • 60 J
  • 30 J
  • 15 J
  • 0
Kinetic energy is present in the following:
  • Water stored in a dam
  • Stretched rubber band
  • Water released from a dam
  • Compressed spring
The force needed to produce an acceleration of $$\displaystyle 6\ { m }/{ { s }^{ 2 } }$$ in a ball of mass $$4\ kg$$ will be:
  • $$24\ N$$
  • $$30\ N$$
  • $$32\ N$$
  • $$20\ N$$
How much energy in kilowatt hour is consumed in operating ten 50 watt bulbs for 10 hours per day in a month (30 days)
  • 1500
  • 5000
  • 15
  • 150
A ball is projected upwards. As it rises, there is increase in its:
  • Momentum
  • Retardation
  • Kinetic energy
  • Potential energy
How much work must be done by a force on $$50\ $$$$kg$$ body in order to accelerate it from rest to $$20\ m/s$$  in $$10\ $$$$s$$ ?
  • $$10^3\ $$$$J$$
  • $$10^4\ $$$$J$$
  • $$2\times 10^3\ $$$$J$$
  • $$4\times 10^4\ $$$$J$$
Work is said to be done if the force and displacement are
  • Parallel to each other
  • Opposite to each other
  • Inclined at an angle with each other $$\theta (\neq 90^{\circ})$$
  • All of the above
The K.E. of a body can be increased maximum by doubling its:
  • mass
  • weight
  • speed
  • density
Complete the following sentence:
The potential energy of a body is the energy by virtue of its _______ .
  • motion
  • position
  • Both A and B
  • None of these
In SI system, the unit of P.E. is :
  • erg
  • dyne-cm
  • joule
  • none of these
Name the type of energy (kinetic energy $$K$$ or potential energy $$U$$) possessed in a compressed spring:
  • $$U$$
  • $$K$$
  • Both $$U$$ and $$K$$
  • None
A ball is thrown vertically up-wards from the ground. Regarding the work done by air resistance, which of the following is correct?
  • Work done is positive
  • Work done is negative
  • Work done is zero
  • Work done may be positive or negative
When we pay for our electricity bill, we are paying for the:
  • charge used.
  • current used.
  • power used.
  • energy used.
The commercial unit of electric energy is $$kilowatt-hour\ (kW h)$$, commonly known as:
  • $$Unit$$
  • $$Faraday$$
  • $$Curie$$
  • None of these
Work done by the gravitational force on a body of mass $$m$$ moving on a smooth horizontal surface through a distance $$s$$ is: (Given acceleration due to gravity $$=g$$):
  • $$mgs$$
  • $$-mgs$$
  • $$0$$
  • $$2 mgs$$
Complete the following sentence:
The kinetic energy of a body is the energy by virtue of its______ .
  • force
  • motion
  • roughness
  • all the above
What is one unit of household electrical energy in J?
  • $$1000\ J$$
  • $$3600\ J$$
  • $$0.6 \times 10^3 J$$
  • $$3.6 \times 10^6 J$$
Which one of the following is not the unit of energy?
  • joule
  • newton metre
  • kilowatt
  • kilowatt hour
An electric heater is rated $$1500 \ W$$. How much energy does it use in $$10 \ hours$$ ?

  • $$25 \: kWh$$
  • $$10 \: kWh$$
  • $$15 \: kWh$$
  • $$12 \: kWh$$
A body at maximum height possesses:
  • Kinetic energy
  • Potential energy
  • Solar energy
  • Heat energy
An electric lamp is marked $$60\ W,\ 220\ V$$. The cost of kilo watt hour of electricity is $$Rs.\ 1.25$$. The cost of using thing lamp on $$220\ V$$ for $$8\ hrs$$ is:
  • $$Rs.\ 0.25$$
  • $$Rs.\ 0.60$$
  • $$Rs.\ 1.2$$
  • $$Rs.\ 4.00$$
The ratio of the total work done or total energy consumed to the total time taken is called:
  • Power
  • Average power
  • Energy
  • Average energy
When a work of 1 joule is done in 1 s, the power is:
  • One kilo watt
  • One watt
  • One watt-second
  • One joule
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