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.
"The position of each element in the table gives important information about its structure, properties, and behavior in chemical reactions. Specifically, an element's position in the periodic table helps you figure out its electron configuration, how the electrons are organized around the nucleus."
Answer: 2.7 m/s
Explanation:
Given the following :
Period (T) = 8.2 seconds
Radius = 3.5 m
The tangential speed is given as:
V = Radius × ω
ω = angular speed = (2 × pi) / T
ω = (2 × 22/7) / 8.2
ω = 6.2857142 / 8.2
ω = 0.7665505
Therefore, tangential speed (V) equals;
r × ω
3.5 × 0.7665505 = 2.6829268 m/s
2.7 m/s