Question

0. The critical wavelength for producing the photoelectric effect in tungsten is 2600 A. What wavelength would be necessary to produce photoelectrons from tungsten having twice the K.E. of those produced at 2200 Å: (A) 2900 A (B) 3000A (C) 1900 A (D) 3500 A​

Answer 1

Answer:

C

Explanation

The critical wavelength of tungsten is also known as the threshold wavelength of material. Thus with the help of threshold wavelength we will find the Kinetic energy of photons. Then we will double this kinetic energy and then we will find the wavelength of photons which will produce that much amount of energy.

hv = hv∘ + K.E

Here, hv is the energy supplied to material, hv∘ is the threshold energy of electrons and K.E represents the kinetic energy of electrons