Question

A light source of frequency, 6 x 1015 Hz is
subjected to a metal sheet having work function
equal to 22.6 eV. Then, the velocity of photo-
electrons emitted having maximum kinetic energy
will be (Planck constant : h = 6.626 10-34 J-s)
(1) 4.43 x 105 m/s
(2) 3.21 x 107 m/s
(3) 8.89 x 105 m/s
(4) 8.73 x 106 m/s​

Answer 1

Answer:

hv= 6.626×6x10-¹²x10-⁴x10-³

= 39.756x10^-19

~ 39.76 x 10^-19

hv°= 22.6×1.6x10^-19

= 36.16x 10^-19

hv=hv°+1/2mv²

1/2mv²= hv-hv° = 3.6 x10^-19

9.1x10^-31 x v² = 7.2 x 10^-19

v² = (7.2/9.1)x 10¹²

v = 0.889 x 10^6 = 8.89 x 10^5