Question

10 power-6ergs are observed by metal 10 power-8 ergs of energy is used as a work function remaining energy is converted as KE calculate KE
​

Answer 1

Answer:

. Work function, ϕ

o

=2.14eV

Frequency of light, ν=6×10

14

Hz

Maximum K.E. is given by the photoelectric effect.

K=hν−ϕ

o

K=(

1.6×10

−19

6.626×10

−34

×6×10

14

)−2.14=0.345eV

(b). For stopping potential, V

o

, we can write the equation for kinetic energy as,

K=eV

o

⇒V

o

=

e

K

=

1.6×10

−19

0.345×1.6×10

−19

=0.345V

(c). The maximum speed of the emitted photoelectrons is v.

Hence, the relation for kinetic energy can be written as,

K=

2

1

mv

2

m=9.1×10

−31

kg is the mass of electron.

⇒v

2

=2K/m

⇒v=3.323×10

5

m/s=332.3km/s