Answer:
A turbine and generator produce the electricity
Explanation:
"A hydraulic turbine converts the energy of flowing water into mechanical energy. A hydroelectric generator converts this mechanical energy into electricity.
ans: B
Kinetic energy = 
= 
= 50J
ps. the height will only affect its potential energy, not kinetic.
Unchanged because ALL objects fall at 9.8m/s^2. Yes, all
The radio waves are electromagnetic wave, so it travels with velocity of light i.e
.
We can use the relation between frequency, wavelength and speed as

Here c is speed of light,
is wavelength and f is frequency and its value is given 99.90 FM, it is actually in megahertz (i.e 99.90 MHz).
Therefore,
.
Thus, the broadcast wavelength of the given radio station is 3.003 m.
Answer:
a) 9.72 mm
b) 4.86 mm
Explanation:
wave length of light λ is 580 nm = 580 \times 10⁻⁹ m
Width of slit d = 0.215\times 10⁻³ m
Distance of screen D = 1.8 m.
Width of one fringe = 
Putting the values we get fringe width
= 
=4.86 mm.
a) Width of central maxima = 2 times width of one fringe
= 2 times 4.86
=9.72 mm
b) width of each fringe except central fringe is same , no matter what the order is.Only brightness changes .
So width of either of the two first order bright fringe will be same and it will be
= 4.86 mm.