Abeam of light with a frequency range from 3.01 × 10 14 hz to 6.10 × 10 14 hz is incident on a metal surface. if the work function of the metal surface is 2.20 ev, what is the maximum kinetic energy of photoelectrons ejected from this surface? ( h = 6.626 × 10 -34 j ∙ s, 1 ev = 1.60 × 10 -19 j)

The maximum kinetic energy of the photoelectrons ejected from the surface is 5.22×10^-20 J.

Explanation:

let h = 6.626×10^-34 J×s be the planck constant.

let f be the frequency of light.

let Ф = 2.20×1.60×10^-19 = 3.52×10^-19 J be the work function.

then, the relationship  between the kinetic energy of photoelectrons K, the energy provided by the light E and the work function of the material is given by:

K = h×f - Ф

  = (6.626×10^-34)×(6.10×10^14) - 3.52×10^-19

  = 5.22×10^-20 J

Therefore, the maximum kinetic energy of the photoelectrons ejected from the surface is 5.22×10^-20 J.

the force on the thing and the distance the force moves the thing

the minimum constant speed at which she can catch the train is 2.7 m/s

given:

acceleration = 0.6

time = 4.5 s

to find:

velocity = ?

formula used:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

solution:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

v = 0 + (0.6 × 4.5)

v = 2.7 m/s

the minimum constant speed at which she can catch the train is 2.7 m/s