Answer:
, repulsive
Explanation:
The magnitude of the electric force between two charged particles is given by Coulomb's law:
where:
is the Coulomb's constant
are the two charges of the two particles
r is the separation between the two charges
The force is:
- repulsive if the two charges have same sign
- Attractive if the two charges have opposite signs
In this problem, we have two electrons, so:
is the magnitude of the two electrons
is their separation
Substituting into the formula, we find the electric force between them:
And the force is repulsive, since the two electrons have same sign charge.
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:
Max height= 36000 meters
Total Time = 120 seconds
Explanation:
0 = U - at
U = at
U= 20*60
U= 1200 m/s
MAX altitude would be
(U²Sin²tita)/2g
Max height= 1200² *( SIN90)²/(2*20)
Time of FLIGHT
2 * 1200/20
2400/20
120 sec
onds
The process of burning fuel is Combustion
