Question

In a photoelectric effect experiment, electromagnetic radiation containing a finite distribution of wavelengths shines on a metal plate and photoelectrons are emitted.
a. When the radiation intensity is increased, the number of photoelectrons emitted by the metal ___.
b. When all of the wavelengths in the radiation are increased by the same amount, the number of photoelectrons emitted by the metal ____.
c. When the work function of the metal is increased, the number of photoelectrons emitted by the metal ___.

Answer 1

Answer with Explanation:

a.Intensity of radiation is directly proportional to the frequency of radiation

When the intensity of radiation  increases then the frequency of radiation increases and therefore, the number of photo-electrons emitted by the metal increases.

b.When all  of the wavelength in the radiation are increased by the same amount

We know that  

$f=\frac{v}{\lambda}$

Frequency is inversely proportional to the wavelength.

Therefore, the frequency decrease .

When the frequency decreases then the number of photo-electrons emitted by the metal decrease.

c.When the work function of the metal is increased  then the gain of kinetic energy decreases .

When energy decreases then the number of photo-electrons emitted by the metal decreases.