291. Heat is transmitted from higher temperature to lower temperature through the actual motion of the molecules in –
1. Conduction
2. Convection
3. Radiation
4. Both conduction and convection
Option “4” is correct. Heat is transmitted from higher temperature to lower temperature through the actual motion of the molecules in both conduction and convection.
292. _____ is same on every point on a rotating body.
1. Linear velocity
2. Linear momentum
3. Angular torque
4. Angular velocity
Option “4” is correct. Angular Velocity is same on every point on a rotating body.
293. The SI unit of electric charge is –
1. Ampere
2. Coulomb
3. Pascal-second
4. Kelvin
Option “3” is correct. The SI unit of electric charge is Coulomb.
294. When a running car stops suddenly, the passengers tends to lean forward because of –
1. Centrifugal force
2. Inertia of rest
3. Inertia of motion
4. Gravitation force
Option “3” is correct. When the bus is running, the whole body of the passenger is in the state of motion. When the bus stops suddenly, the lower part of the passengers body which is in contact with the bus, comes to rest. But the passenger’s upper portion remains in the state of motion due to the inertia of motion. This is the reason for the passenger to lean forward when the bus stops suddenly.
295. If a boy is sitting in a train, which is moving at a constant velocity throws a ball straight up into the air, the ball will –
1. Fall in front of him
2. Fall behind him
3. Fall into hand
4. None of the above
Option “3” is correct. If a boy is sitting in a train, which is moving at a constant velocity throws a ball straight up into the air, the ball will fall into his hand.
296. A person is hurt on kicking a stone due to –
1. Inertia
2. Velocity
3. Reaction
4. Momentum
Option “3” is correct. A person is hurt on kicking a stone due to reaction. Here Newton third law of motion is applied which states that every action has equal and opposite reaction.
297. For a body moving with non-uniform acceleration –
1. Displacement-time graph is linear
2. Displacement-time graph is non-linear
3. Velocity-time graph is non-linear
4. Velocity-time graph is linear
Option “3” is correct. For a body moving with non-uniform acceleration, the velocity -time graph is nonlinear.
298. The Sky appears blue due to-
1. Blue color is scattered most
2. The red color is scattered most
3. Blue light is minimum absorbed by atmosphere
4. Red light is ultimately absorbed by atmosphere
Option “1” is correct. Blue light which has the least wavelength of all the visible radiations is scattered most. The blue appearance of the sky is due to scattered light which enters the eyes.
299. For shaving, one uses-
1. Concave mirror
2. Plain mirror
3. Convex mirror
4. None of these
Option “1” is correct. People use a concave mirror for shaving because when a man standing between the principal focus and pole of a concave mirror, he sees as enlarged, the erect and virtual image of his face.
300. Which of the following lens is used to minimize Myopia?
1. Convex lens
2. Concave lens
3. Cylindrical lens
4. None of these
Option “2” is correct. A concave lens is used to remove the defect of myopia.
