Option “1” is correct. The working principle of a washing machine is based on centrifugation force. The term centrifugal force is used to refer to an inertial force or fictitious force, particular to a particle moving on a circular path that has the same magnitude and dimensions as the force the keeps the particle on its circular path but the point in the opposite direction.
122. In a three-pin electrical plug longest pin should be connected to-
1. Ground terminal
2. Live terminal
3. Neutral terminal
4. Any terminal
Option “1” is correct. In the three-pin plug, there are three ends namely live, neutral and earth. The earth pin on a plug is longer than the line and neutral pins. This means the earth pin is the first to connect and last to disconnect for safety of electrical device. It provides an alternative and easy path for leakage or fault current flow.
123. The electric current does not flow between two properly connected charged bodies if they are having-
1. Same charge
2. Same capacity
3. Same resistivity
4. Same potential
Option “4” is correct. According to Ohm’s law, if there is a potential difference (V) across a resistor then there is a current (I) flowing through it. Current flows in a circuit as a result of difference in potential between two points in the circuit.
124. Small drops of the same size are charged to V volts each. If n such drops coalesce to form a single large drop, its potential will be:
1. n^(2/3) V
2. n^(1/3) V
3. n V
4. N^- V
Option “1” is correct. Potential of large drop = n^(2/3) V
125. Light is made of seven colours. What is the method of separating the colours?
1. The colours can be separated by a prism
2. The colours can be separated by a filter
3. The colours can be separated by plants
4. The colours cannot be separated
Option “1” is correct. Colours could be separated by using a prism.
126. The strongest force in nature is –
1. Electrical force
2. Gravitational force
3. Nuclear force
4. Magnetic force
Option “3” is correct. Strong nuclear force is the strongest force. It is present inside the atom responsible for binding the protons and neutrons and also inside the proton and neutron in binding up the quarks.
127. In nuclear reactor, heavy water is used as –
1. Coolant
2. Fuel
3. Moderator
4. Atomic smasher
Option “3” is correct. Heavy water is basically used as a moderator in nuclear reactors to slow down the neutrons so that they are captured and become effective to bring about the fission reaction.
128. Increasing the amount of a substance does not change its-
1. Volume
2. Weight
3. Mass
4. Density
Option “4” is correct. Density of an object depends on its mass and volume. Density can be found by using the equation: Density = Mass/Volume
129. The smallest unit of length is-
1. Micron
2. Nanometre
3. Angstrom
4. Fermimetre
Option “4” is correct.
130. The time taken to reach the Sunlight up to the surface of earth is approximately-
1. 4.2 sec
2. 4.8 sec
3. 8.5 minutes
4. 3.6 hrs.
Option “3” is correct. The sunlight takes about 500 second or 8.5 minutes to reach to the earth.
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