Because the waves in the water with the fan like system.
Answer: 430 nm.
Explanation:
The relation of wavelength and frequency is:
Formula used : 
where,
= frequency =
= wavelength = ?
c = speed of light = 
Now put all the given values in this formula, we get
Thus the wavelength (in nm) of the blue light emitted by a mercury lamp is 430 nm.
The advantages of generating electricity using a hydroelectric power station rather than wind turbines is that it's not polluting anything since it's regular water. It also can be used over and over again.
The disadvantages of using a hydroelectric power station is that it can be very deadly and cause damage to towns if it overfills or falls apart releasing all the water. Since nothing lasts forever, eventually they will break apart and would require everyone to evacuate before doing so. Another disadvantage is that it disrupts migration of animals that live in the water such as fish.
It's better than wind turbines because wind turbines require a lot of wind to turn and on days without wind, very little energy can be produced.
Answer:
The law of inertia relates to revolution of planets round the sun due to constant motion of the planets round the sun.
Explanation:
Law of inertia states that a body at rest or uniform motion will continue to be at rest or uniform motion unless it is acted upon by an external force.
The gravitational force keeps the planets revolving round the sun in a uniform motion, this will continue till infinity unless equal and opposite force acts on our planets.
Therefore, the law of inertia relates to revolution of planets round the sun due to constant motion of the planets round the sun.
