# Spectrum and Its Relationship to Temperature

by | Sep 22, 2022 | Physics, Experiments

Contents

## Introduction

In this experiment (Spectrum and Its Relationship to Temperature), we will determine the temperature of two different light sources by measuring their maximum intensities with the help of a spectrum. To find the approximate temperature, we will put the corresponding wavelength of maximum intensity in Wein’s law. We also need to contact the light sensor company to calibrate the result we received from the light sensor to get the true light source temperature.

## Aim

To determine the temperature of two different light sources by measuring their maximum intensities with the help of a spectrum.

## Theory

The black-body radiation curve for different temperatures will peak at different values of wavelengths, which are inversely proportional to temperature. This is called Wein’s displacement law.

λ = b/T

Where λ = wavelength,

b = constant of proportionality

T = temperature ## Requirements

1. Vernier light sensor,

3. Yardstick.

4. Flashlight,

6. Macintosh computer,

7. Data logger program,

8. Diffraction grating,

9. He-Ne laser calibrate.

## Theory

Step 1: For each light source, measure the angle of diffraction.

Step 2: From each light source, receive the maximum intensity.

Step 3: Calibrate the obtained information.

Step 4: Find the maximum wavelength.

Step 5: With the help of Wein’s law, find the temperature.

Step 6: Compare the result.

## Observation

1. Overhead projector has a lower wavelength. That’s why it has a higher temperature.

2. We also measured the solar spectrum, and the temperature came out really low compared to past results and tests.

## Result

1. The light sensor has an uneven spectral response and before we make any conclusion, we have to contact the manufacturer of the Vernier light sensor.

2. After calibrating the result, we can compare the true temperature of the light source, and we can find information using the Vernier light sensor.

## Precaution

1. Measure the angle of diffraction carefully.

2. Compare the result after consulting the manufacturer of the light source.

## Conclusion

In this way to measure and compare the temperature of the light source through the visible spectrum, Wenz’s law, corresponding wavelength, and maximum intensities.

## Viva Questions with Answers

Q.1 What was the aim of your experiment?

ANS. To determine the temperature of two different light sources by measuring their maximum intensities with the help of a spectrum.

Q.2 What do you understand about the angle of diffraction?

ANS. The angle between the normal and the reflected rays is called the angle of diffraction.

Q.3 What do you know about Wenz’s law?

ANS. The black-body radiation curve for different temperatures will peak at different values of wavelengths, inversely proportional to temperature. This is called Wein’s displacement law.

Q.4 What is the formula for Wenz’s law?

ANS. λ = b/T

Where, λ = wavelength,

b = constant of proportionality

T = temperature

Q.5 Why the overhead projector has a higher temperature?

ANS. We find that the overhead projector has a greater wavelength because of which it has a higher temperature.