When a metal was exposed to light at a frequency of 4.07× 1015 s–1, electrons were emitted with a kinetic energy of 3.30× 10–19 J. What is the maximum number of electrons that could be ejected from this metal by a burst of light (at some other frequency) with a total energy of 3.39× 10–7 J?

Respuesta :

Answer :  The maximum number of electrons released = [tex]1.432\times 10^{12}electrons[/tex]

Explanation : Given,

Frequency = [tex]4.07\times 10^{15}s^{-1}[/tex]

Kinetic energy = [tex]3.30\times 10^{-19}J[/tex]

Total energy = [tex]3.39\times 10^{-7}J[/tex]

First we have to calculate the work function of the metal.

Formula used :

[tex]K.E=h\nu -w[/tex]

where,

K.E = kinetic energy

h = Planck's constant = [tex]6.626\times 10^{-34}J/s[/tex]

[tex]\nu[/tex] = frequency

w = work function

Now put all the given values in this formula, we get the work function of the metal.

[tex]3.30\times 10^{-19}J=(6.626\times 10^{-34}J/s\times 4.07\times 10^{15}s^{-1})-w[/tex]

By rearranging the terms, we get

[tex]w=2.367\times 10^{-18}J[/tex]

Therefore, the works function of the metal is, [tex]2.367\times 10^{-18}J[/tex]

Now we have to calculate the maximum number of electrons released.

The maximum number of electrons released = [tex]\frac{\text{ Total energy}}{\text{ work function}}[/tex]

The maximum number of electrons released = [tex]\frac{3.39\times 10^{-7}J}{2.367\times 10^{-19}J}=1.432\times 10^{12}electrons[/tex]

Therefore, the maximum number of electrons released is [tex]1.432\times 10^{12}electrons[/tex]