Grade 9 physics mcqs with answers

UNIT NO. 1 PHYSICAL QUANTITIES AND MEASUREMENT.

1.      The number of base units in SI are:

a.       3

b.      6

c.       7

d.      9

2.      Which one of the following is not a derived unit?

a.       Pascal

b.      Kilogram

c.       Newton

d.      Mole

3.      Amount of a substance in terms of numbers is measured in:

a.       Gram

b.      Kilogram

c.       Newton

d.      mole

4.      An interval of 200μs is equivalent to

a.       0.2 s

b.      0.02 s

c.       2x10^-4 s

d.      2x10^-6 s

5.      Which one of the following is the smallest quantity?

a.       0.01 g

b.      2mg

c.       100μg

d.      5000ng

6.      Which instrument is most suitable to measure the internal diameter of a test tube?

a.       Meter rule

b.      Vernier calipers

c.       Measuring tape

d.      Screw gauge

7.      A student claimed the diameter of a wire as 1.032 cm using Vernier calipers. Up to what extent do you agree with it?

a.       1 cm

b.      1.0cm

c.       1.03 cm

d.      1.032 cm

8.      A measuring cylinder is used to measure

a.       Mass

b.      Area

c.       Volume

d.      Level of a liquid

9.      A student noted the thickness of a glass sheet using a screw gauge. On the main scale, it reads 3 divisions while 8^th division on the circular scale coincides with index line. Its thickness is:

a.       3.8 cm

b.      3.08 mm

c.       3.8 mm

d.      3.08 m

10.  Significant figures in expression are:

a.       All the digits

b.      All the accurately known digits

c.       All the accurately known digits and the first doubtful digit

d.       All the accurately known and all the doubtful digits

UNIT NO. 2 KINEMATICS

11.  A body has a translatory motion if it moves along a

a.       Straight line

b.      Circle

c.       Line without rotation

d.      Curved path

12.  The motion of a body about an axis is called

a.       Circular motion

b.      Rotatory motion

c.       Vibratory motion

d.      Random motion

13.  Which of the following is a vector quantity?

a.       Speed

b.      Distance

c.       Displacement

d.      Power

14.  If an object is moving with constant speed then its distance time graph will be straight line.

a.       Along time-axis

b.      Along distance-axis

c.       Parallel to time axis

d.      Inclined to time axis

15.  A straight line parallel to time axis on a distance-time graph tells that the object is

a.       Moving with constant speed

b.      At rest

c.       Moving with variable speed

d.      In motion

16.  The speed- time graph of a car is shown in the figure, which of the following statement is true?

a.       Car has an acceleration of 7.5 ms^-2

b.      Car has constant speed of 7.5 ms^-1

c.       Distance travelled by the car is 75 m

d.      Average speed of the car is 15 ms^-1

 

17.  Which one of the following graph is representing uniform acceleration?

    

18.  By dividing displacement of moving body with same time, we obtain

a.       Speed

b.      Acceleration

c.       Velocity

d.      Deceleration

19.  A ball is thrown vertically upward. Its velocity at the highest point is:

a.       -10 ms^-1

b.      Zero

c.       10 ms^-2

d.      None of these

20.  A change in position is called:

a.       Speed

b.      velocity

c.       Displacement

d.      Distance

21.  A train is moving at the speed of 36 kmh^-1. Its speed expressed in ms^-1 is:

a.       10 ms^-1

b.      20 ms^-1

c.       25 ms ^-1

d.      30 ms ^-1

22.    A car starts from rest. It acquires a speed of  25 ms^-1 after 20 s. the distance moved by the car during this time is:

a.       31.25 m

b.      250m

c.       500m

d.      5000m

UNIT NO. 3 DYNAMICS

23.  Newton’s first law of motion is only valid in the absence of:

a.       Force

b.      Net force

c.       Friction

d.      Momentum

24.  Inertia depends upon

a.       Force

b.      Net force

c.       Mass

d.      Velocity

25.  A boy jumps out of a moving bus. There is danger for him to fall:

a.       Towards the moving bus

b.      Away from the bus

c.       In the direction of motion

d.      Opposite to the direction of the motion

26.  A string is stretched by two equal and opposite forces 10 N each. The tension in the string is:

a.       Zero

b.      5 N

c.       10N

d.      20 N

27.  A mass of a body:

a.       Decrease when accelerated

b.      Increase when accelerated

c.       Decrease when moving with high velocity

d.      None of the above.

28.  Two bodies of masses m₁ and m₂ attached to the ends of an inextensible strings passing over a frictionless pulling such that both move vertically. The acceleration of bodies is:

                             

29.  Which of the following is the unit of momentum?

a.       Nm

b.      kgms^-2

c.       Ns

d.      Ns^-1

30.  When a horse pull a cart, the action is on the:

a.       Cart

b.      Earth

c.       Horse

d.      Cart and horse

31.  Which of the following materials lowers the friction when pushed between metal plates?

a.       Water fine

b.      marble powder

c.       Air

d.      Oil

UNIT NO. 4

TURNING EFFECT OF FORCES

32.  Two equal but unlike parallel forces having different line action produce:

a.       A torque

b.      A couple

c.       Equilibrium

d.      Neutral equilibrium

33.  The number of perpendicular components of a force are:

a.       1

b.      2

c.       3

d.      4

34.  The number of  forces that can be added by head to tail rule are:

a.       1

b.      3

c.       4

d.      Any number

35.  A force of 10 N is making an angle of 30° with the horizontal. Its horizontal component will be:

a.       4N

b.      5N

c.       7N

d.      8.7N

36.  A couple is formed by:

a.       Two forces perpendicular to each other

b.      Two like parallel forces

c.       Two equal and opposite forces in the same line

d.      Two equal and opposite forces not in the same line

37.  A body is in equilibrium when its:

a.       Acceleration is uniform

b.      Speed is uniform

c.       Speed and acceleration is uniform

d.      Acceleration is zero

38.  A body is in neutral equilibrium when its centre of gravity:

a.       Is at its highest position

b.      Is at the lowest position

c.       Keeps its height if displaced

d.      Is situated at its bottom

39.  Racing cars are made stable by:

a.       Increasing their speed

b.      Decreasing their mass

c.       Lowering their centre of gravity

d.      Decreasing their width

UNIT NO. 5

GRAVITATION

40.  Earth’s gravitational force of attraction vanishes at

a.       6400 km

b.      Infinity

c.       42300 km

d.      1000 km

41.  Value of g increases with the

a.       Increase in mass of the body

b.      Increase in altitude

c.       Decrease in altitude

d.      None of the above

42.  The value of g at the height one earth’s radius above the surface of the earth is:

a.       2g

b.     

c.      

d.     

43.  The value of g on moon’s surface is 1.6 ms^-2. What will be the weight of the 100 kg body of the moon?

a.       100N

b.      160N

c.       1000N

d.      1600N

44.  The altitude of geostationary orbits in which communication satellites are launched above the surface area of the earth is:

a.       850 km

b.      1000km

c.       6400km

d.      42300 km

45.  The orbital speed of low orbit satellite is:

a.       Zero

b.      8 ms^-1

c.       800ms^-1

d.      8000ms^-1

UNIT NO. 6

WORK AND ENERGY

46.  The work done will be zero when the angle between the force and the distance is

a.       45°

b.      60°

c.       90°

d.      180°

47.  If the direction of the motion of the force is perpendicular to the direction of the motion of the body then work done will be

a.       Maximum

b.      Minimum

c.       Zero

d.      None of these

48.  If the velocity of the body becomes double then its kinetic energy will

a.       Remain the same

b.      Becomes double

c.       Becomes four times

d.      Become half

49.  The work done in lifting a brick of mass 2 kg through the height of 5 m above ground will be

a.       2.5 J

b.      210 J

c.       50 J

d.      100 J

50.  The kinetic energy of a body of mass 2 kg is 25 J. Its speed is

a.       5 ms^-1

b.      12.5 ms^-1

c.       25 ms^-1

d.      50 ms^-1

51.  Which one of the following converts light energy into electrical energy?

a.       Electric bulb

b.      Electric generator

c.       Photocell

d.      Electric cell

52.  When a body is lifted through a height h the work done on it appears in the form of its:

a.       Kinetic energy

b.      Potential energy

c.       Elastic potential energy

d.      Geothermal energy

53.  The energy stored in coal is

a.       Heat energy

b.      Kinetic energy

c.       Chemical energy

d.      Nuclear energy

54.  The energy stored in dam is

a.       Electric energy

b.      Potential energy

c.       Kinetic energy

d.      Thermal energy

55.  In Einstein’s mass-energy equation c is the

a.       Speed of sound

b.      Speed of light

c.       Speed of electron

d.      Speed of earth

56.  Rate of doing work is called

a.       Energy

b.      Torque

c.       Power

d.      momentum 

UNIT NO. 7

PROPERTIES OF MATTER

57.  In which of the following state molecules do not leave their position?

a.       Solid

b.      Liquid

c.       Gas

d.      Plasma

58.  Which of the substance is the lighter one?

a.       Copper

b.      Mercury

c.       Aluminum

d.      Lead

59.  SI unit of pressure is Pascal, which is equal to:

a.       10⁴ Nm^-2

b.      1 Nm^-2

c.       10² Nm^-2

d.      10³ Nm^-2

60.  What should be the approximate length of a glass tube to construct a water barometer?

a.       0.5 m

b.      1 m

c.       2.5 m

d.      11 m

61.  According to the Archimedes, up thrust is equal to

a.       Weight of displaced  liquid

b.      Volume of displaced  liquid

c.       Mass of displaced  liquid

d.       None of the above

62.  The density of a substance can be found with the help of:

a.       Pascal law

b.      Hooke’s law

c.       Archimedes principle

d.      Principle of floatation

63.  According to Hooke’s law

a.       Stress × strain=constant

b.      Stress / strain=constant

c.       Strain / stress=constant

d.      Stress = strain

The following force- extension graphs of a spring are drawn on the same scale. Answer the following questions given below from viii to x.

64.  Which graph does not obey Hooke’s law

a.         b.    c.   d.

65.  Which graph gives the smallest value of spring constant?

a.         b.     c.   d.

66.  Which graph gives the largest value of spring constant?

a.         b.    c.   d.

UNIT NO. 8

THERMAL PROPERTIES OF MATTER

67.  Water freezes at

a.       0 °F

b.      32°F

c.       -273K

d.      0 K

68.  Normal human body temperature is

a.       15 °C

b.      37°C

c.       37° F

d.      98.6°C

69.  Mercury is used as thermometric material because it has

a.       Uniform thermal expansion

b.      Low freezing point

c.       Small heat capacity

d.       All the above properties

70.  Which of the following material has large specific heat?

a.       Copper

b.      Ice

c.       Water

d.      mercury

71.  Which of the following materials has large value of temperature coefficient of linear expansion?

a.       Aluminum

b.       Gold

c.       Brass

d.      steel

72.  What will be the value of  for a solid for which has a value of 2×10^-5K^-1?

a.       2×10^-5K^-1

b.      6×10^-5K^-1

c.       8×10^-15K^-1

d.      8×10^-5K^-1

73.  A large water reservoir keeps the temperature of nearby land moderate due to

a.       Low temperature of water

b.      Low specific heat of water

c.       Less absorption of heat

d.      Large specific heat of water

74.  Which of the following affects evaporation?

a.       Temperature

b.      Surface area of the liquid

c.       Wind

d.      All of the above

UNIT NO. 9

TRANSFER OF HEAT

75.  In solids, heat is transferred by:

a.       Radiation

b.      Conduction

c.       Convection

d.      Absorption

76.  What happens to the thermal conductivity of a wall if its thickness is doubled?

a.       Becomes double

b.      Remains the same

c.       Becomes half

d.      Becomes one fourth

77.  Metals are good conductors of heat due to the:

a.       Free electrons

b.      Big size of their molecules

c.       Small size of their molecules

d.      Rapid vibrations of their atoms

78.  In gases, heat is mainly transferred by

a.       Molecular collision

b.      Conduction

c.       Convection

d.      Radiation

79.  Convection of heat is the process of heat transfer due to the:

a.       Random motion of molecules

b.      Downward movement of molecules

c.       Upward movement of molecules

d.      Free movement of molecules

80.  False ceiling is done to

a.       Lower the height of ceiling

b.      Keep the roof clean

c.       Cool the room

d.      Insulate the ceiling

81.  Rooms are heated using gas heaters by

a.       Conduction only

b.      Convection and radiation

c.       Radiation only

d.      Convection only

82.   Land breeze blows from

a.       Sea to land during night

b.      Sea to land during the day

c.       Land to sea during night

d.      Land to sea during the day

83.  Which of the following is a good radiator of heat?

a.       A shining silvered surface

b.      A dull black surface

c.       A white surface

d.      A green colored surface

 01.                       C

02.                       B

03.                       D

04.                       D

05.                       D

06.                       B

07.                       C

08.                       C

09.                       B

10.                       C

11.                       C

12.                       B

13.                       C

14.                       C

15.                       B

16.                       A

17.                       A

18.                       C

19.                       B

20.                       C

21.                       A

22.                       B

23.                       C

24.                       C

25.                       C

26.                       D

27.                       D

28.                       B

29.                       C

30.                       D

31.                       D

32.                       B

33.                       D

34.                       B

35.                       D

36.                       D

37.                       D

38.                       C

39.                       C

40.                       B

41.                       C

42.                       D

43.                       B

44.                       D

45.                       D

46.                       C

47.                       C

48.                       C

49.                       D

50.                       A

51.                       C

52.                       B

53.                       C

54.                       B

55.                       B

56.                       C

57.                       A

58.                       C

59.                       B

60.                       D

61.                       A

62.                       C

63.                       B

64.                       C

65.                       D

66.                       A

67.                       B

68.                       B

69.                       D

70.                       C

71.                       A

72.                       B

73.                       D

74.                       D

75.                       B

76.                       A

77.                       A

78.                       C

79.                       D

80.                       D

81.                       B

82.                       C

83.                       B