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.
Answer:
A
Explanation:
There are three basic forces in aerodynamics: acceleration, which moves an airplane forward; drag, which holds it back; and height, which keeps it airborne. Lift is generally explained by three theories: Bernoulli's principle, the Coanda effect, and Newton's third law of motion.
Explanation:
The height of the rise of liquid with capillary tube is given by the formula as follows :
Where
r is radius
It is clear that the height of the rise of liquid is inversely proportional to the radius of the capillary tube.
If the radius of the capillary tube is doubled, it means the height of rise of liquid with capillary tube become half.
<span>Fossil Record</span>
<span>Geologic Time Scale</span>
