Photo electric effect experiment - Determination of Planck's constant and Work function.

Summary

This video explains an experiment to determine Planck's constant and the work function using the photoelectric effect. It outlines the necessary apparatus, including a micro ammeter, voltmeter, metal surface, and filters. The experiment involves shining light on the metal surface, adjusting the voltage to stop the current, and measuring the stopping potential for different light filters. The procedure is repeated for blue, green, orange, and red filters, with corresponding stopping potentials recorded. The video concludes with instructions to graph the results and perform calculations in the next segment.

Takeaways

• 😀 The experiment aims to determine the Planck's constant and the work function using the photoelectric effect.
• 😀 Key apparatus required for the experiment include a micro ammeter, voltmeter, light source, metal surface, filters, and an incandescent bulb.
• 😀 The photoelectric effect involves light striking a metal surface, causing the emission of electrons.
• 😀 The metal surface in the experiment faces the light source, and the emitted electrons create a measurable current.
• 😀 The micro ammeter measures the current (in microamperes) and the voltmeter measures the voltage (in volts).
• 😀 The stopping potential is the voltage required to reduce the current to zero, which is an essential part of the experiment.
• 😀 Different color filters (blue, green, orange, red) are used in the experiment to investigate how the stopping potential changes.
• 😀 The stopping potential for the blue color filter is recorded as 0.787 V.
• 😀 For the green color filter, the stopping potential is 0.617 V.
• 😀 The orange color filter gives a stopping potential of 0.465 V.
• 😀 For the red color filter, the stopping potential is 0.280 V.
• 😀 After obtaining the stopping potential for each filter color, a graph should be plotted, and calculations for the experiment are discussed in a subsequent video.

Q & A

What is the aim of the experiment described in the script?

The aim of the experiment is to determine the work function of a metal surface and the Planck's constant using the photoelectric effect.

What apparatus is required for the experiment?

The required apparatus includes a micro ammeter, voltmeter, light source (incandescent bulb), metal surface, filters (in different colors), and a power switch.

How is the photoelectric effect demonstrated in the experiment?

The photoelectric effect is demonstrated when light incident on a metal surface causes the emission of electrons. This is used to measure current and potential.

What is the function of the micro ammeter in this experiment?

The micro ammeter is used to measure the current produced when electrons are emitted from the metal surface upon light exposure.

Why is the voltage adjusted during the experiment?

The voltage is adjusted to make the current zero. This voltage is called the stopping potential, which prevents the emitted electrons from reaching the micro ammeter.

What does the stopping potential indicate in this experiment?

The stopping potential is the voltage required to stop the current of emitted electrons from the metal surface. It is different for each color filter used in the experiment.

What is the procedure for measuring the stopping potential for each color filter?

For each color filter, the light is first directed onto the metal surface, and the voltage is increased until the current is reduced to zero. The corresponding stopping potential is then recorded.

How do the stopping potential values vary with different color filters?

The stopping potential decreases with decreasing frequency of the light, meaning the blue filter requires the highest stopping potential, while the red filter requires the lowest.

What happens when the light is switched on in the experiment?

When the light is switched on, it strikes the metal surface, causing electrons to be emitted. The current begins to flow, which can be measured by the micro ammeter.

What is the significance of the filters used in the experiment?

The filters are used to control the frequency of light incident on the metal surface. Different filters correspond to different light frequencies, which affect the emission of electrons and the stopping potential.