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Angle of the prism using Spectrometer





Switch On/Off Light : Used to switch on/off the light.

Place Prism/Remove Prism : This switch used to place the prism on the prism table or remove prism from the prism table.



Slit focus : This slider used to focus the slit while looking through telescope.

Slit width : Using this slider, width of the slit can be adjusted.

Telescope: Using this slider one can move the telescope from its position.

Vernier Table: Vernier table can be rotate using this slider.


    Fine Angle adjustment

Telescope: This is used to fine adjust the telescope.

Vernier Table: Using this slider , we can rotate fine angle.



Here we get the zoomed view of vernier I and II by placing mouse pointer over it.





Preliminary adjustments:


    Performing simulator


  • Focus Telescope on distant object.
  • When focus is correct, start button is activated. Then click Start button.
  • Switch on the light by clicking Switch On Light button.
  • Focus the slit using Slit focus slider.
  • Adjust the slit width using Slit width slider.
  • Coincide the slit with cross wire in the telescope. 


    Performing Real Lab:


  1. Turn the telescope towards the white wall or screen and looking through eye-piece, adjust its position till the cross wires are clearly seen.
  2. Turn the telescope towards window, focus the telescope to a long distant object.
  3. Place the telescope parallel to collimator.
  4. Place the collimator directed towards sodium vapor lamb. Switch on the lamp.
  5. Focus collimator slit using collimator focusing adjustment.
  6. Adjust the collimator slit width.
  7. Place prism table, note that the surface of the table is just below the level of telescope and collimator.
  8. Place spirit level on prism table. Adjust the base leveling screw till the bubble come at the centre of spirit level.
  9. Clamp the prism holder.
  10. Clamp the prism in which the sharp edge is facing towards the collimator, and base of the prism is at the clamp.


Least Count of Spectrometer


One main scale division (N)  =................minute

Number of divisions on vernier (v) = ................

L.C    = «math xmlns=¨http://www.w3.org/1998/Math/MathML¨»«mfrac»«mi»N«/mi»«mi»v«/mi»«/mfrac»«/math» = .......................minute


To determine the angle of the Prism:


    Performing simulator 


  • Click Place Prism button.
  • Place the edge of prism, pointed towards collimator.
  • Move the telescope using Telescope slider, up to see the slit on side. Make coincide the slit with the cross wire using fine angle adjusting slider. Then note the reading in the tabular coloumn.
  • Move the telescope in the opposite direction and do the same.
  • Find the difference between two angle ie 2θ. Hence, find the angle of prism i.e θ.

    Performing Real Lab: 


  1. Prism table is rotated in which the sharp edge of the prism is facing towards the collimator.
  2. Rotate the telescope in one direction up to which the reflected ray is shown through the telescope.
  3. Note corresponding main scale and vernier scale reading in both vernier (vernier I and vernier II).
  4. Rotate the telescope in opposite direction to view the reflected image of the collimator from the second face of prism.
  5. Note corresponding main scale and vernier scale reading in both vernier(vernier I and vernier II).
  6. Find the difference between two readings, i.e.θ
  7. Angle of prism, A=θ/2

 Mean 2«math xmlns=¨http://www.w3.org/1998/Math/MathML¨»«mi»§#952;«/mi»«/math»      =..................Degrees

Angle of prism A =..................Degrees 




Angle of the Prism, A =……………………………….Degrees





Cite this Simulator:

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