I think that the best one is determining one's sense of individuality and place in society.
Answer:
3 photons
Explanation:
The energy of a photon E can be calculated using this formula:

Where
corresponds to Plank constant (6.626070x10^-34Js),
is the speed of light in the vacuum (299792458m/s) and
is the wavelength of the photon(in this case 800nm).

Tranform the units

The band Gap is 4eV, divide the band gap between the energy of the photon:

Rounding to the next integrer: 3.
Three photons are the minimum to equal or exceed the band gap.
It's either 3 or 4 I know this becuase I have read a book about electricity
Answer:
21 m/s.
Explanation:
The computation of the wind velocity is shown below:
But before that, we need to find out the angles between the vectors
53° - 35° = 18°
Now we have to sqaure it i.e given below
v^2 = 55^2 + 40^2 - 2 · 55 · 40 · cos 18°
v^2 = 3025 + 1600 - 2 · 55 · 40 · 0.951
v^2 = 440.6
v = √440.6
v = 20.99
≈ 21 m/s
Hence, The wind velocity is 21 m/s.