Isaac Physics Help!

i need some help with this isaac physics question, any help would be appreciated! i have no clue how to answer.

https://isaacphysics.org/questions/phys19_d6_q4?board=bfl22_photoelectric_effect&stage=a_level

Calculate the maximum speed of the photoelectrons emitted when a material with an 8.4×10^−20J work function is illuminated by light of frequency 7.0×10^14Hz.

Reply 1

ashleemx

2

this post is a couple days old, but if you're still stuck;

use Kmax=hf - work function to find the maximum kinetic energy,
then use K=1/2mv^2 to find the equation for velocity
the mass isn't given in the question, but the mass of an electron is a fundamental unit, and you've just worked out the kinetic energy. so rearrange the equation and plug in the values to find your answer 🙂

Reply 2

depriveofsocial

OP

12

Original post by ashleemx

this post is a couple days old, but if you're still stuck;

use Kmax=hf - work function to find the maximum kinetic energy,
then use K=1/2mv^2 to find the equation for velocity
the mass isn't given in the question, but the mass of an electron is a fundamental unit, and you've just worked out the kinetic energy. so rearrange the equation and plug in the values to find your answer 🙂