Chapter 38, Problem 27A

(a)

To determine

Whether the brightness or frequency of the light determines the kinetic energy of the ejected electrons.

Explanation of Solution

Introduction:

The photoelectric effect is the effect in which the electrons from a metal surface ejected due to the incident light on the surface.

When light incident on a surface then the energy of the photon transfers to electrons of the surface. The energy of the electron increases due to the energy of the photon. The energy of the photon provides the kinetic energy for the ejection of the electron from the surface.

The energy of the photon depends on the frequency of the light. The frequency of the bright light is high. If the frequency of the incident light increases then the energy of the photon also increase, so the kinetic energy of the ejected electrons.

Conclusion:

The brightness or frequency of the light determines the kinetic energy of the ejected electrons in the photoelectric effect.

(b)

To determine

The factor that determines the number of the ejected electrons.

Explanation of Solution

Introduction:

The energy of the electron increases due to the energy of the photon. The energy of the photon provides the kinetic energy for the ejection of the electron from the surface.

The energy of the photon excite the electrons of the surface. If the more energy of the photon incidents on the surface then the more electrons ejected from the surface. The energy of the photon increases due to the frequency of the light. The frequency of the light determines the number of ejected electrons from the surface.

Conclusion:

The frequency of the light determines the number of ejected electrons from the surface.