. .
Cornus Experiment

An alternate method to access flash content 

Simulation link: https://vlab.amrita.edu/repo/PHY/OPT/CornusMethod/CornusMethod.swf




1. Real lab


To find the diametre of rings without mass



  1. Place the given Perspex beam symmetrically over the two knife edges.
  2. A convex lens is placed over beam.
  3. As shown in figure light is allowed to fall normally on the air film with the help of glass plate.
  4. On focusing, interference fringes formed are viewed by means of travelling microscope.
  5. Fix the cross wire on any of the nth ring on one side (left or right) using the knob.
  6. Corresponding value of MSR and VSR is noted.
  7. Move the cross wire to the (n-1)th or (n-2)nd ring on the same side.
  8. Take the readings of the rings on either side of the centre position.
  9. Now repeat the same procedure by moving the cross wire up and down on either side of centre position.




Diametre of rings with mass


  1. Adjust the distance between the weight hanger and the knife edges.
  2. Add mass on the weight hanger.
  3. Repeat steps 4-9 to measure the horizontal and vertical position of rings.




2. Simulator


To find the diametre of rings without mass


  1. Mass on weight hanger is set as zero g.
  2. Select desired values for the variables by clicking on the sliders for each variable.
  3. Click on the ‘Light On’ button.
  4. Now the repeat the steps 5-9 of real lab.
  5. The reading of rings during the horizontal/vertical motion is shown by the horizontal/vertical position value of microscope under variables section.
  6. Click ‘Reset’ button for another values of variables

To find the diametre of rings with mass


  1. Adjust the variables and position of weight hanger by clicking on their corresponding sliders.
  2. Add suitable mass on weight hanger.
  3. Repeat steps 3-6 of simulator.




To find the thickness of Perspex beam using screw gauge


                                                         Zero correction=

                                                                    Thickness of Perspex beam, b=………..mm



To find the breadth of Perspex beam using Vernier calipers


                                                        Breadth of plate, a=…………cm


To find the diameter of rings in horizontal direction



                                           λ=………..nm, l=………cm


                                  Longitudinal bending R«math xmlns=¨http://www.w3.org/1998/Math/MathML¨»«mfrac»«mn»1«/mn»«mrow»«mn»4«/mn»«mi»n«/mi»«mi»§#955;«/mi»«/mrow»«/mfrac»«mfrac»«mrow»«msub»«msup»«mi»d«/mi»«mrow»«mo»§apos;«/mo»«mn»2«/mn»«/mrow»«/msup»«mi»n«/mi»«/msub»«msub»«msup»«mi»d«/mi»«mn»2«/mn»«/msup»«mi»n«/mi»«/msub»«/mrow»«mrow»«mo»(«/mo»«msub»«msup»«mi»d«/mi»«mn»2«/mn»«/msup»«mi»n«/mi»«/msub»«mo»-«/mo»«msub»«msup»«mi»d«/mi»«mrow»«mo»§apos;«/mo»«mn»2«/mn»«/mrow»«/msup»«mi»n«/mi»«/msub»«mo»)«/mo»«/mrow»«/mfrac»«mo»§nbsp;«/mo»«mo»§nbsp;«/mo»«mo»§nbsp;«/mo»«mo»§nbsp;«/mo»«mo»§nbsp;«/mo»«mo»§nbsp;«/mo»«/math»


To find the diameter of rings in vertical direction



                           Lateral strain, R2  «math xmlns=¨http://www.w3.org/1998/Math/MathML¨»«mfrac»«mn»1«/mn»«mrow»«mn»4«/mn»«mi»n«/mi»«mi»§#955;«/mi»«/mrow»«/mfrac»«mfrac»«mrow»«msub»«msup»«mi»d«/mi»«mrow»«mo»§apos;«/mo»«mo»§apos;«/mo»«mn»2«/mn»«/mrow»«/msup»«mi»n«/mi»«/msub»«msub»«msup»«mi»d«/mi»«mn»2«/mn»«/msup»«mi»n«/mi»«/msub»«/mrow»«mrow»«mo»(«/mo»«msub»«msup»«mi»d«/mi»«mn»2«/mn»«/msup»«mi»n«/mi»«/msub»«mo»-«/mo»«msub»«msup»«mi»d«/mi»«mrow»«mo»§apos;«/mo»«mo»§apos;«/mo»«mn»2«/mn»«/mrow»«/msup»«mi»n«/mi»«/msub»«mo»)«/mo»«/mrow»«/mfrac»«mo»§nbsp;«/mo»«mo»§nbsp;«/mo»«mo»§nbsp;«/mo»«mo»§nbsp;«/mo»«mo»§nbsp;«/mo»«mo»§nbsp;«/mo»«/math»




For a given plate


  1. Young’s modulus, Y=………………Nm-2
  2. Poisson’s ratio, σ =…………………
  3. Bulk modulus, b =………………….. Nm-2


Cite this Simulator:

..... .....

Copyright @ 2021 Under the NME ICT initiative of MHRD

 Powered by AmritaVirtual Lab Collaborative Platform [ Ver 00.13. ]