11th class (Fsc) Physics unit 5 MCQs
76. The ratio of velocity of disc to velocity of hoop is:
a. 2/3
b. 2/√3
c. 4/3
d. 4/√3
77. The ratio of rotational K.E of hoop to its translation K.E is:
a. 1:1
b. 1:2
c. 1:4
d. 2:1
78. The relation between the speed of disc and hoop can be written as:
a. Vdisc=Vhoop
b. Vdisc= √3/4Vhoop
c. Vdisc= √1/2Vhoop
d. Vdisc= √4/3Vhoop
79. The linear velocity of a disc when it reaches the bottom of an inclined plane of height “h”is:
a. √2/3gh
b. √gh
c. √1/3gh
d. √4/3gh
80. The ratio of moment of inertia of hoop to the moment of inertia of disc (if their masses and radii are same) is equal to:
a. 4
b. 2
c. 1/4
d. 1/2
81. The formula for speed of satellite orbiting around the Earth is:
a. V = √gR
b. V = √2gr
c. V = √gR/M
d. V = √2gR
82. If the radius of earth is doubled then the value of critical velocity becomes:
a. √2Vo
b. 1/√2Vo
c. 1/4 V
d. 1/2 Vo
83. Satellites are the objects that orbit around the:
a. Earth
b. Moon
c. Star
d. Sun
84. The expression for the time period of low flying satellite put into the orbit is:
a. T = 2𝜋R/R
b. T = 2𝜋R/g
c. T = 2𝜋R/v
d. T = 2𝜋R/G
85. If the radius of Earth is increased to four times of the present. Critical velocity vo becomes:
a. 2Vo
b. Vo/√2
c. 1/2Vo
d. √2Vo
86. Artificially gravity can be created in the space ship by:
a. Increasing its velocity
b. Revolving around the earth
c. Decreasing its velocity
d. Spinning around its own axis
87. Satellites are held in orbit by the gravitational pull of:
a. Earth
b. Moon
c. Star
d. Sun
88. The maximum velocity necessary to put a satellite into orbit is:
a. 7.9 kms-1
b. 7.1 kms-1
c. 8.9 kms-1
d. 7.3 kms-1
89. The value of a time period of a low flying satellite is:
a. 28 hours
b. 1 year
c. 1 day
d. 84 minutes
90. The value ‘g’ at the centre of the earth is:
a. 3g
b. Infinite
c. Zero
d. 2g
91. Close orbiting satellites orbit the earth at a height of about:
a. 4000m
b. 400km
c. 400cm
d. 4000km
92. Close orbiting satellites orbits the earth at a height of about:
a. 400 m
b. 400 km
c. 400 cm
d. 4000Km
93. Which is unimportant in describing the satellite’s orbit?
a. Mass of inertia
b. Distance of satellite from earth’s center
c. Mass of earth
d. Gravitational constant
94. A man of 1 kg is free falling. The force of gravity is:
a. Reduced to zero
b. Increased
c. Not changed
d. Decreased
95. The weight of the body at the centre of the earth is:
a. zero
b. Maximum
c. Infinite reason
d. Minimum
96. If a rocket is accelerating upward with an acceleration of 2g, an astronaut of weight, mg in the rocket shows apparent weight:
a. 2mg
b. Zero
c. 3mg
d. Mg
97. Apparent weight of a man in upward accelerated lift will:
a. Remain same
b. Increases
c. Increase then decrease
d. Decreases
98. A man weight 1000N in a stationary lift. If the lift moves up with an acceleration of 10m/s2 ,then its weight becomes:
a. 3000 N
b. 1000 N
c. 0 N
d. 2000 N
99. A man of mass 5kg is falling freely, the force acting on it will be:
a. 19.6 N
b. 5N
c. Zero
d. 9.8 N