Stopping Potential Formula with Example

Stopping potential  :

Stopping potential of kinetic energy Kmax (j) in joules is equal to the product of electron e© in coulomb and multiply the stopping potential v0(v) in volts. Hence the stopping potential equation can be written as,

Kmax (j)=e©* v0(v)

V0= Kmax/e

Where,

Kmax→ kinetic energy in joules

V0→ stopping potential in volts

E→ electrons in coulomb

Example:1

Calculate the stopping potential ?In a work function of metal 3.45 ev and the light of frequency 6*1014 Hz is moving  on the metal surface, photoemission of electrons occurs.

Answer:

Work function of metal φ=3.45 ev

Frequency v=6.0*1014 HZ

As we know

K=hv – φ0

Where

H=planck’s constant=6.626*10-34 js

K=6.626*1034*6*1014 /1.6 *10-19-3.45

=2.485-3.450=0.965ev

Hence, the maximum kinetic energy of the emitted electron is 0.345 ev

For stopping potential as we know the equation for kinetic energy as

K=ev0

V0=K/e

=0.965*1.6*10-19 /1.6*10-19=0.965v

So the stopping potential of the material is 0.965v

Example:2

Calculate the stopping potential ? In a work function of metal 2.14 ev and the light of frequency 6*1014 Hz is moving  on the metal surface, photoemission of electrons occurs.

Answer:

Work function of metal φ=2.14 ev

Frequency v=6.0*1014 HZ

As we know

K=hv – φ0

Where

H=planck’s constant=6.626*10-34 js

K=6.626*1034*6*1014 /1.6 *10-19-2.14

=2.485-2.140=0.345ev

Hence, the maximum kinetic energy of the emitted electron is 0.345 ev

For stopping potential as we know the equation for kinetic energy as

K=ev0

V0=K/e

=0.345*1.6*10-19 /1.6*10-19=0.345v

So the stopping potential of the material is 0.345v

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