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The work function for platinum is 6.35 eV. (a) Convert the value of the work fun

ID: 1744777 • Letter: T

Question

The work function for platinum is 6.35 eV. (a) Convert the value of the work function from electron volts tojoules.
J

(b) Find the cutoff frequency for platinum.
Hz

(c) What maximum wavelength of light incident on platinum releases photoelectrons fromthe platinum's surface?
m

(d) If light of energy 7.2 eV isincident on platinum, what is themaximum kinetic energy of the ejected photoelectrons? Give theanswer in electron volts.
eV

(e) For photons of energy 7.2 eV, what stopping potential would be requiredto arrest the current of photoelectrons?
V Please Help (a) Convert the value of the work function from electron volts tojoules.
J

(b) Find the cutoff frequency for platinum.
Hz

(c) What maximum wavelength of light incident on platinum releases photoelectrons fromthe platinum's surface?
m

(d) If light of energy 7.2 eV isincident on platinum, what is themaximum kinetic energy of the ejected photoelectrons? Give theanswer in electron volts.
eV

(e) For photons of energy 7.2 eV, what stopping potential would be requiredto arrest the current of photoelectrons?
V Please Help

Explanation / Answer

   a.   1   eV   =   1.6* 10-19   J          Workfunction      =   6.35   eV   =   6.35* 1.6 * 10-19   =   1.016* 10-18   J    b.      =   h* f0          cut offfrequency   f0   =   10.16* 10-19 / 6.62 *10-34   =   1.534 *1015   Hz    c.   Maximum (threshold)wavelength   0   =   c/ f0   =   3.0 *108 / 1.534 * 1015             0   =   1.956* 10-7   m    d.   Photoelectric equationis             Kmax   =   h* f   -       max. k.e. ofphotoelectrons   Kmax   =   7.2eV   -   6.35   eV   =   0.85   eV    e.   Also   Kmax   =   e* V0          0.85eV   =   e * V0                 Stoppingpotential   V0   =   0.85   V                 Stoppingpotential   V0   =   0.85   V