The first excited state of a particular atom in a gas is 5.8 eV above the ground state. A moving electron collides with one of these atoms, and excites the atom to its first excited state. Immediately after the collision the kinetic energy of the electron is 3.7 eV. What was the kinetic energy of the electron just before the collision? Ki = eV

E₀ = 9.5 eV

Explanation:

In the processes of absorption, excitation and shocks the energy must be conserved therefore the energy before the shock is

         E₀ = E_excitation + E_residual

         E₀ = 5.8 + 3.7

         E₀ = 9.5 eV

this is the energy of the electron before the collision

d₁ = displacement of tern from arctic to antarctic = 11000 miles

d₂ = displacement of tern from antarctic to arctic =   - 11000 miles

d = total displacement for the journey

total displacement for the journey is given as

d = d₁ + d₂

d = 11000 + (-11000)

d = 0 miles

t₁ = time of travel from arctic to antarctic = 3 months = 3 x 30 days = 90 days

t₂ = time of travel from antarctic to arctic = 3 months = 3 x 30 days = 90 days

t = total time of travel

total time of travel is given as

t = t₁ + t₂

t = 90 + 90

t = 180 days

average velocity is given as

average velocity = total displacement/ total time

v = d/t

v = 0/180

v = 0 miles/day