GK - Physics
16.
Centrifugal force increases with
Answer
Centrifugal force is the fictitious force that pulls out from the center on the body we feel while moving in the circular path. It increases with the rate of rotation of the axis i.e, acceleration of the body.
Answer :
Option CExplanation :
Centrifugal force is the fictitious force that pulls out from the center on the body we feel while moving in the circular path. It increases with the rate of rotation of the axis i.e, acceleration of the body.
17.
A voltaic cell converts chemical energy to
Answer
An electrochemical cell that converts the chemical energy of spontaneous redox reactions into electrical energy is known as a galvanic cell or a voltaic cell.
Answer :
Option BExplanation :
An electrochemical cell that converts the chemical energy of spontaneous redox reactions into electrical energy is known as a galvanic cell or a voltaic cell.
18.
The focal length of a plane mirror is
Answer
A plane mirror can be considered as a spherical mirror of infinite radius of curvature. Focal length is half of radius of curvature and hence it is infinity.
Answer :
Option DExplanation :
A plane mirror can be considered as a spherical mirror of infinite radius of curvature. Focal length is half of radius of curvature and hence it is infinity.
19.
It is easier to roll a barrel full of coal tar than to pull it because
Answer
When a body slides over another body, the resistance faced is due to sliding friction. On the other hand if the body rolls over another body, the resistance offered is less and is called as rolling friction. Rolling friction is less than the sliding friction. Thus it is easier to roll a barrel full of coal tar than to pull it.
Answer :
Option BExplanation :
When a body slides over another body, the resistance faced is due to sliding friction. On the other hand if the body rolls over another body, the resistance offered is less and is called as rolling friction. Rolling friction is less than the sliding friction. Thus it is easier to roll a barrel full of coal tar than to pull it.
20.
Heat transfer horizontally within the atmosphere is called
Answer
The horizontal transfer of heat by the wind is called advection. Advection is a transport mechanism of a substance or conserved property by a fluid due to the fluid's bulk motion. An example of advection is the transport of pollutants or silt in a river by bulk water flow downstream.
Answer :
Option DExplanation :
The horizontal transfer of heat by the wind is called advection. Advection is a transport mechanism of a substance or conserved property by a fluid due to the fluid's bulk motion. An example of advection is the transport of pollutants or silt in a river by bulk water flow downstream.
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