The photoelectric effect is a phenomenon where electrons are emitted from a material when it is exposed to light. The energy of the incident light is transferred to the electrons, causing them to be ejected. The maximum kinetic energy of the emitted electrons can be determined using the photoelectric cut off voltage and the work function of the material.

Understanding the Photoelectric Cut Off Voltage:
The photoelectric cut off voltage is the minimum voltage that needs to be applied to stop the flow of photoelectrons. It is the point at which the kinetic energy of the emitted electrons is equal to the energy required to overcome the work function of the material.

Determining the Work Function:
The work function is the minimum amount of energy required to remove an electron from the material. In this experiment, the work function for the material used was found to be 4.2 eV (electron volts).

Calculating the Maximum Kinetic Energy:
To calculate the maximum kinetic energy of the emitted electrons, we can use the equation:

Maximum Kinetic Energy = Energy of the Incident Light - Work Function

The energy of the incident light can be determined by converting the photoelectric cut off voltage from volts to electron volts. In this case, the photoelectric cut off voltage was found to be 1.5 V.

1 electron volt (eV) is equivalent to 1.6 x 10^-19 Joules. So, to convert the voltage to electron volts, we can multiply it by this conversion factor:

1.5 V * (1.6 x 10^-19 J/eV) = 2.4 x 10^-19 J

Now, we can calculate the maximum kinetic energy:

Maximum Kinetic Energy = 2.4 x 10^-19 J - 4.2 eV

To convert the work function from electron volts to joules, we can multiply it by the conversion factor:

4.2 eV * (1.6 x 10^-19 J/eV) = 6.72 x 10^-19 J

Maximum Kinetic Energy = 2.4 x 10^-19 J - 6.72 x 10^-19 J

Maximum Kinetic Energy = -4.32 x 10^-19 J

Since kinetic energy cannot be negative, the maximum kinetic energy of the emitted electrons in this experiment is 0.

1.5eV