Einstein proposed that electrons on the surface of a metal gradually absorb energy from photons until they have enough energy to leave the surface. true or false?

True.

Explanation:

This phenomenon is called the photoelectric effect. Einstein was awarded with the Nobel Prize in 1921 "for his services to Theoretical Physics, and especially for his discovery of the law of the photoelectric effect."

The electrons are bound to the metal surfaces by the attractive force between the positive ions on the surface and the negative charge of the electrons. When the electrons absorb enough energy from the photons to overcome this attractive force, they can leave the surface.

im sorry i dont know

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