Assertion (A) : The rotor blades of wind - turbine execute rotational motion when moving air impinges on them.
Reason (R) : The momentum of the moving air is transferred to the moving blades.
Choose the correct answer :
Assertion (A) Analysis
Statement (A) is correct. The rotor blades of a wind turbine are designed to rotate when wind impinges upon them. This is the fundamental principle of how wind turbines operate, converting wind's kinetic energy into rotational mechanical energy.
Reason (R) Analysis
Statement (R) is also correct. Moving air possesses momentum. When this air interacts with the turbine blades, there is a transfer of momentum from the air to the blades. This interaction involves a change in the air's momentum, resulting in a force on the blades.
Evaluating the Explanation
While both statements are true, Reason (R) is not the primary or correct explanation for Assertion (A). The rotational motion of the blades is primarily caused by the aerodynamic lift force, not just the simple transfer of momentum (which would imply a direct push). The blades are shaped like airfoils; as wind flows over them, a pressure difference is created, generating lift that results in torque and rotation. Momentum transfer is involved but secondary to the lift principle for efficient rotation.
Therefore, both Assertion (A) and Reason (R) are correct, but (R) does not correctly explain (A).
Important Questions from Renewable Energy - Teaching
- Arrange the following in descending order of installed capacity of total solar power as of August, 2025:
A. Gujarat
B. Rajasthan
C. Maharashtra
D. Tamil Nadu
Choose the correct answer from the options given below: - Given below are two statements one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): A wind mill will be more effective if it is placed at a higher elevation above the ground than a lower one.
Reason (R): Generally, the wind speed increases with altitude above the earth's surface.
In the light of the above statements, choose the most appropriate answer from the options given below: - The biogas is a mixture of
(1) Methane and ethane
(2) Methane and hydrogen
(3) Ethanol and methane
(4) Oxygen and butane Geothermal power plants are much like fossil and nuclear plants with exception of no requirements of:
A. Vapour dominated hydrothermal resources
B. Boiler
C. Fission reactor
D. Turbine generator
Choose the correct answer from the options given below:
Given below are two statements. One labelled as Assertion (A) and the other labelled as Reason (R) :
Assertion (A) : OTEC power plants have low efficiences.
Reason (R) : Efficiency is governed by 2nd law of thermodynamics.
Choose the correct answer :
