Last updated on Friday, October 6th, 2023
Using a Diffraction Grating experiment in the Physics Lab, how to determine LASER (Light Amplification by Stimulated Emission of Radiation) wavelength . For this just take a LASER source, a grating (here grating have 15000 lines per inch), and a screen to observe the diffraction pattern.
Set-up Diffraction Grating Experiment in Physics Lab
Procedure for Diffraction Grating Experiment
When a LASER light passes through the Grating its diffracted and a pattern develops on the screen with central maxima. Diffraction is a phenomenon of light, in which wave light bends at the edges of an obstacle, if and only if the size of the obstacle is comparable to the wavelength of the light. These diffracted waves superimpose further and a constructive interference appears on the screen. If your aim is to find the wavelength by this experiment then, first find the single slit width; that is known as the grating element and denoted by “d”. This you can find out from the lines that are mentioned on the grating as here 15000 LPI.
One inch is 2.54 cm so 15,000 lines are in 2.54 cm so one line will be equal to 2.54/15000 cm. This is 1.69×10^ (-4)cm approximately.
We have to use nk=2d sin theta
where k is the wavelength; that is to be found from observation
n= is the order of diffraction
d= is the grating element
and theta is the angle between the line (distance between the screen and grating) and first maxima on either side if an observation is for the first order.
Analysis of Results
we have already found out the “d” grating element, n=1 for first order now we have to find the “theta” that can be find out using the “Tan theta” i.e. basically ratio of the distance from central maxima to the first order maxima (you can say Y) and the distance between screen and grating that is D. Now “tan theta = Y/D” from this you can find the theta which can be used to calculate the value of “sin theta”. Now you can put these value and find the result for wavelength (lambda). You can take different observations for the “theta”….by varying the distance “D” and “Y”. Take the average and find the wavelength.
Now compare this result with the standard value of the laser light and check the percentage error. Your % error is the result of varying designing parameters of the LASER (Light Amplification by the Stimulated Emission of Radiation) and manual error.
Frequently Asked Questions about Diffraction Grating Experiment
Question: Which laser is used in diffraction grating experiment?
Answer: In diffraction grating experiments, a variety of lasers can be used depending on the specific requirements of the experiment. However, helium-neon (He-Ne) lasers and diode lasers are commonly employed for these experiments due to their stability, narrow spectral lines, and ease of use.
He-Ne lasers emit red or green light and have a well-defined wavelength, making them suitable for many diffraction experiments.
Question: What is the principle of grating experiment?
Answer: A diffraction grating is a device with many closely spaced slits or rulings, and it is used to disperse light into its component colors or create interference patterns.
Question: What is a diffraction grating experiment?
Answer: A diffraction grating experiment is a scientific investigation that uses a diffraction grating to study the properties of light.
Question: Why is it called diffraction grating?
Answer: A diffraction grating is called so because it is a device designed to exploit the phenomenon of diffraction to disperse light into its component colors or wavelengths.
Question: Why do we use a diffraction grating in this experiment?
Answer: One of the primary purposes of using a diffraction grating is to determine the wavelengths of light. Diffraction gratings disperse light into its component colors (spectrum) or create interference patterns, which can be precisely measured.
Question: What is diffraction grating type?
Answer: Transmission Grating: In transmission gratings, the rulings are transparent, and light passes through them. They are often made by ruling closely spaced lines on a glass or plastic substrate. Transmission gratings are commonly used in spectroscopy and optics.
Question: What is a diffraction grating experiment?
Answer: A diffraction grating experiment is a scientific investigation or optical experiment that uses a diffraction grating to study the properties of light and its interaction with the grating.
Question: What is diffraction grating and its formula?
Answer: The formula that describes the behavior of a diffraction grating is known as the grating equation. The grating equation relates the angles at which light of different wavelengths (colors) appears in the diffraction pattern to the wavelength of the light and the properties of the grating. The grating equation is typically written as:
nλ = d * (sin θ)
Where:
n is the order of the diffraction maximum (an integer).
λ is the wavelength of light.
d is the spacing between adjacent rulings or slits on the diffraction grating.
θ is the angle at which the diffracted light is observed.
In the grating equation, you can use it to find the angle (θ) at which a specific order (n) of a particular wavelength (λ) appears in the diffraction pattern when you know the grating spacing (d).
For a given order (n) and wavelength (λ), you can rearrange the equation to solve for the angle (θ):
θ = sin^(-1)(nλ / d)
Question: Which laser is used in grating?
Answer: He-Ne gas LASER
Question: What material is grating?
Answer: Diffraction gratings can be made from various materials, and the choice of material depends on the specific requirements of the experiment or application. Usually Glass and Plastic.
Question: What are the advantages of diffraction?
Question: What material is used for diffraction grating?
Question: Which light is used in diffraction grating?
Question: What is the formula for diffraction grating experiment?
Question: How is diffraction grating made?
Question: What are 5 applications of diffraction grating?
