The work function of an element is the energy required to remove an electron from the surface of the solid. the work function for rubidium is 218.1 kj/mol (that is, it takes 218.1 kj of energy to remove 1 mole of electrons from 1 mole of rb atoms on the surface of rb metal). what is the maximum wavelength of light that can remove an electron from an atom in rubidium metal?

λ = 548.7 nm

Explanation:

Hi!

First we want to know how much energy we need to remove 1 electron from the surface of the solid:

218.1 kJ/mol => 218 100 J / (6.022 x 10^23) electrons

                             = 3.621 x 10^-19 J/electron  

That is we need 3.621 x 10^-19 J to remove one electron

Now we can calculate the wavelength that a photon must have in order to have this energy:

E = (hc) / λ

λ = (hc) / Ε

where

 h = 6,626070150(69) ×10 -34 Js (wikipedia)

 c = 3 x10^8 m/s

hc = 1.987 x 10^-25 Jm

Therefore:

λ = ( 1.987 x 10^-25 /3.621 x 10^-19 ) m = 5.487 x 10^-7 m

λ = 548.7 nm

acceleration = (change in speed) / (time for the change)

change in speed = (20-120)= -100 m/s.

1.5 min = 90 sec

acceleration = -100/90 = -1.11 m/s^2.

we don't care about the 150kg or the 2,500 meters. they don't make any difference.

read more on -

another example of kinetic energy would be,

kinetic energy   >     moving energy

answer   >   letter choice (c),   a hammer falling off a table.

hope that !                                         : )