Answer:
D. Wind turbines take up a lot of space.
Explanation:
In wind turbines the kinetic energy received by the air molecules is converted into electrical energy by the use of turbines
So here in order to get more kinetic energy from air we need more crossectional area of the wind mill to interact with the air
So here we need the large size of turbines
so this is the main disadvantage of the wind turbines because it needs large area to install the whole setup also the efficiency of this turbine is small so it needs large number of wind mills to setup good output power
so correct answer will be
D. Wind turbines take up a lot of space.
Answer:
The force on the grass hopper is equal and opposite to the force on the wind shield.
Explanation:
It is a known fact every action has an equal and opposite reaction. Here the action force is the grasshopper hitting the windshield.
The reaction force is the force exerted by the windshield on the grasshopper.
If the force of windshield on the grasshopper is more, grasshopper would have been thrown away. If the grasshopper's force on the windshield is greater, the windshield would have broken.
But here these constitute equal and opposite action-reaction pair of forces and so the grasshopper is able to repeatedly strike the windshield.
Explanation:
It is given that the number of electrons passing through the cross-sectional area in 1 s is 
. Also, we know that charge on an electron is 
, then negative charge crossing to the left per second is as follows.
I- = 
I- = 0.544 A
As it is given that the number of protons crossing per second is 
, as the charge on the proton is 
, then positive charge crossing to the right per second is calculated as follows.
I+ = 
I+ = 0.224 A
I = l I+ l + l I- l
So, I = 0.544 + 0.224
= 0.768 A
Thus, we can conclude that the current in given hydrogen discharge tube is 0.768 A.
Answer: the ball with the less volume.
To count density you need to divide the mass by the volume. That means larger mass will be more density, but larger volume means lower density. In this case, the ball has the same mass. So the one with less volume has more density.
