Corey Boyd Dec 11, 2020

light of wavelength 400 nm strikes a certain metal which has a photoelectric work function of 2.13ev find out maximum kinetic energy of the photoelectrons

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Answer:

Given :

Wavelength = 400 nm
Work function = 2.13eV

To find :

Maximum Kinetic energy (KE) of photoelectron

Formula used :

$\sf \bullet \:\: KE_{max} \: =\dfrac{hc}{ \lambda}- W_0$

Here,

h = Planck's constant

c = speed of light

$\sf \bullet\: KE_{max}\: =\: kinetic\: energy \\\\ \sf \bullet \lambda \:=\: wavelength \\ \\ \sf \bullet W_{0} \: = \: work\: function$

Solution :

Putting given value in above formula, we get;

$\sf \implies\: KE_{max} \:=(\dfrac{ \:\: 6.626 \times{10}^{ - 34}\times\: 3\: \times \: {10}^{8}\:}{400 \times{10}^{ - 9} } \: ) -\: (2.13 \times 1.6 \times{10}^{ - 19})\\\\ \sf \implies\: KE_{max} \:=(\dfrac{19.878}{4}\times{10}^{ - 19} ) \:-\: (3.408 \times{10}^{ - 19} ) \\\\ \sf \implies\: KE_{max} \:= (4.9695 \times{10}^{ - 19} ) -\: (3.408 \times{10}^{ - 19} ) \\\\ \sf \implies\: KE_{max} \:= (4.9695 \:-\: 3.408) \:\times{10}^{ - 19}\\\\ \sf \implies\: KE_{max} \:= 1.5651 \:\times\:{10}^{ - 19}\: J \\\\ \sf \implies\: KE_{max} \:\approx \: 1.57 \times{10 }^{ - 19}\: J$

ANSWER :

Maximum Kinetic energy of photoelectron = $\sf \bold{1.57\: \times 10^{-19}}$

423

Jesus Barnes

Dec 11, 2020

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