Answered

It takes 281.7 kJ of energy to remove 1 mole of electrons from the atoms on the surface of lithium metal. If lithium metal is irradiated with 261-nm light, what is the maximum kinetic energy the released electrons can have

Answer :

Answer:

The maximum kinetic energy of electron is = 2.93 × [tex]10^{-19}[/tex] Joule

Explanation:

We know that total energy

[tex]E = \frac{hc}{\lambda}[/tex]  ------------ (1)

Here h = plank's constant = 6.62 × [tex]10^{-34}[/tex] J s

c = speed of light = 3 × [tex]10^{8}[/tex] [tex]\frac{m}{s}[/tex]

[tex]\lambda[/tex] = 261 nm = 261  × [tex]10^{-9}[/tex] m

Put all these values in equation (1) we get

E = 7.6   × [tex]10^{-19}[/tex] J

We know that

Total energy = Energy to remove an electron + K.E of electron

Energy to remove an electron = [tex]\frac{281.7 (1000)}{(6.023)10^{23} }[/tex]

Energy to remove an electron = 4.67  × [tex]10^{-19}[/tex] J

K.E of electron = Total energy - Energy to remove an electron

K.E of electron = 7.6   × [tex]10^{-19}[/tex] -  4.67  × [tex]10^{-19}[/tex]

K.E of electron = 2.93 × [tex]10^{-19}[/tex] Joule

Therefore the maximum kinetic energy of electron is = 2.93 × [tex]10^{-19}[/tex] Joule