The photoelectric cut-off voltage in a certain experiment is 1.5 V. What is the maximum kinetic energy of photoelectrons emitted?

To determine the maximum kinetic energy of photoelectrons emitted in a photoelectric experiment, we can use the relationship between the cut-off voltage and the kinetic energy of the emitted electrons. The cut-off voltage, also known as the stopping potential, is the minimum voltage needed to stop the most energetic photoelectrons from reaching the anode. This voltage directly relates to the kinetic energy of the electrons.

Understanding the Relationship

The kinetic energy (KE) of the emitted photoelectrons can be calculated using the formula:

KE = eV

In this equation:

• KE is the maximum kinetic energy of the photoelectrons (in joules).
• e is the elementary charge, approximately equal to 1.6 x 10^-19 C.
• V is the cut-off voltage (in volts).

Calculating Maximum Kinetic Energy

Given that the cut-off voltage in your experiment is 1.5 V, we can substitute this value into our equation:

KE = (1.6 x 10^-19 C) x (1.5 V)

Now, performing the multiplication:

KE = 2.4 x 10^-19 J

Interpreting the Result

This result indicates that the maximum kinetic energy of the emitted photoelectrons is 2.4 x 10^-19 joules. To put this into perspective, this energy is quite small on a macroscopic scale, but it is significant at the atomic and subatomic levels, where such energies are typical for electron behavior.

Real-World Application

The concept of photoelectric cut-off voltage and the kinetic energy of photoelectrons is fundamental in various applications, including:

• Photovoltaic cells: Understanding how light energy is converted into electrical energy.
• Photoelectron spectroscopy: Analyzing materials by studying the energies of emitted electrons.
• Quantum mechanics: Exploring the particle-wave duality of light and matter.

In summary, the maximum kinetic energy of the photoelectrons emitted in your experiment is 2.4 x 10^-19 joules, which illustrates the fascinating interplay between light and matter in the realm of quantum physics.