• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Diffraction Grating with White Light Source

Extracts from this document...

Introduction

Physics Laboratory Report

The number and the name of the experiment:

Experiment C3- Diffraction Grating with White Light Source
The date of experiment:19 / 5 / 08image00.jpg

Objectives

  • Estimate the wavelength of the light using a diffraction grating
  • Measure the angle of diffraction by simple geometry
  • Measure the angle of diffraction by simple spectrometer
  • Learn the techniques in using a spectrometer

image01.jpg

Apparatus

meter rule

2

set square(woodblock)

2

Clip

1

Diffraction grating(300 lines per mm)

1

ray box with vertical filament

1

12 V low voltage power supply

1

long pin

2

spectrometer

1

laboratory jack

1

color filter – red, green, blue

1 each

sodium lamp(optional)

1

Theory

In the visible wavelengths of the electromagnetic spectrum, red, with the longest wavelength, is diffracted most; and violet, with the shortest wavelength, is diffracted least. Because each color is diffracted a different amount, each color bends at a different angle. The result is a separation of white light into the seven major colors of the spectrum or rainbow. The diffraction grating consists of many narrow slits provided for the diffraction of the light.image02.jpg

Constructive interference occurs between waves from A traveling in the direction AA1 and waves from B traveling in the direction BB1.

...read more.

Middle

1  can be obtained using the formula tanΘ =

Finally, by substituting the values of Θ1and d

into the equation d sinθ1 = 1λ, the required

 wavelength can be calculated.

Procedures

  1. Use the ray box with vertical filament. Place the lamp about 2 m away.
  1. Place two meter rules at right angles to each other as shown. Set the diffraction grating vertically at one end of the meter rule. Observe the horizontal diffraction pattern (color spectrum) of the filament by viewing through the diffraction grating.
  1. Ask the partner to move a long pin to the observer’s left hand side along the other meter rule until it lines up with the middle of the red band of the first order spectrum. Place the red filter in front of the lamp to helping locating the position.
  1. Repeat step 3 for the position on the observer’s right hand side with another pin. Find the separation, 2x, of the pins. Record the results in the table provided.
  1. Repeat step 3 and 4 for green and then blue.
  1. Determine the angles of diffraction for red, green and blue light.
...read more.

Conclusion

Discussion

  • Whether it is better to use pins with the addition of laser bean rather than just pins to locate the position of the light to be found.

Explanation﹕Absolutely, it is better to accept this replacement. The principle of using the pins is to move the pins along the either side of the meter rule until it lines up with the middle of the red band of the first order spectrum in order in order to find out the exact position of the required light. As using the naked eyes to judge the middle point of the red region within its wide range is already really difficult, if we just use the mechanical work (moving the pins) to match up with the observer’s observation, tremendous error will exist due to the inexact human sensate system. Thus, by using the laser bean, we can first point out the relative middle position of the light, then moving the pins along the meter rule until it coincides with the infra-red light. It is no doubt that it will increases the accuracy of the results taken.

...read more.

This student written piece of work is one of many that can be found in our AS and A Level Waves & Cosmology section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related AS and A Level Waves & Cosmology essays

  1. Peer reviewed

    What affects the voltage output of a solar panel?

    3 star(s)

    0.31 0.000494 50 0.27 0.27 0.27 0.27 0.000400 55 0.25 0.24 0.23 0.24 0.000331 60 0.20 0.20 0.20 0.20 0.000278 65 0.19 0.18 0.17 0.18 0.000237 70 0.15 0.15 0.16 0.15 0.000204 75 0.14 0.13 0.13 0.13 0.000178 80 0.10 0.11 0.11 0.11 0.000156 85 0.10 0.09 0.10 0.10 0.000138

  2. How power produced by a solar cell is affected by its distance from a ...

    more intense light as it was cool and working more efficiently and changed as I recorded my experiment. I found that the background light before turning the light on I took measurements at 10 different distances and repeated them three times.

  1. Estimating the wavelength of light using a double-slit and a plane diffraction grating

    Procedure Using a double-slit 1. The laboratory was blacked out. The apparatus was set up as shown in Fig.3. 2 shutter holes were on the compact light source. The one through which the filament of the lamp inside was seen as a short vertical line was opened.

  2. Investigate any relationship present between the distance between a solar cell and a lamp, ...

    1 1 1 95 1 1 1 1 100 1 1 1 1 On this table are the results of the first experiment. In this experiment, I varied the power supplied to the lamp to see the output to the solar cell.

  1. The aim of my coursework is to calculate the wavelength of red laser light ...

    the next one after is called 2nd order spectrum and so on. Calculation using the diffraction grating These below steps show the calculation when using the diffraction grating which then will be followed by the calculation when using the slits as they both have a slightly different method.

  2. Refractive index by tracing light rays

    = 0.2724 / 1.5777 x 100% � 17.3 % Part B: Refractive index of water by critical angle method Trial 1 2 3 4 5 % error in c 0.794 % 0.806 % 0.820 % 0.800 % 0.806 % Percentage error in critical angle of glass block between water-glass interface

  1. I am doing an investigation in to how much a metre rule bends when ...

    * When the mass is added to the rule the bend can then be recorded as accurately as possible by the vertical rule. * The results, which will give a suitable range by being repeated two or three times, depending on the consistency of the readings, can be put in to tables and the averages will be calculated.

  2. Study the interference of light using Helium - Neon Diode Laser.

    A permanent bright band is then obtained at O. Generally, a permanent bright band is obtained at any point Y if the path difference, BY - AY, is given by BY - AY = Where is the wavelength of the sources, A, B and n = 0, 1 2 and so on We now see that permanent interference between

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work