This is a question on the photoelectric effect: For potassium, the work function is 3.65E-19J. Find the maximum wavelength of light that will cause photoelectrons to be emitted when shone onto potassium.

We know thatphoton energy = minimum energy needed to free an electron + max kinetic energy of emitted photoelectronAs we have been asked for the maximum wavelength , we know these photoelectrons just have enough energy to leave the surface of the potassium, but they will not have any kinetic energy. Therefore:photon energy = min energy needed to free electron (work function) E = hf = work function as v = f * wavelengthwork function = (hv)/wavelength, therefore rearranging we get wavelength = (hv) / work function wavelength = (6.63x10-34 x 3.00x108)/(3.65x10-19)= 5.4493x10-7m = 5.45x10-7m (to 3s.f)

KB
Answered by kathryn b. Physics tutor

2105 Views

See similar Physics A Level tutors

Related Physics A Level answers

All answers ▸

A 12V lamp, 36W is switched on for 1 hour. Find the energy supplied by the battery.


A passenger is standing in a train. The train accelerates and the passenger falls backwards. Use Newton's first law of motion to explain why he fell backwards.


Explain the Doppler Shift Effect, and how it can be used to measure blood flow in the body.


What is the difference between a scalar and a vector? Give 3 examples of each.


We're here to help

contact us iconContact usWhatsapp logoMessage us on Whatsapptelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

© MyTutorWeb Ltd 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences