Page 2 - 10-phy-12 Geometrical Optics
P. 2
Materials Glass slab, drawing board, thumb pins, common pins, sheet of paper, pencil,
Required protractor and ruler.
1. Fix the paper sheet on the drawing board with the help of thumb pins.
Procedure 2. Place a rectangular glass slab on the sheet and mark its boundary
ABCDA.
3. Remove the slab and draw an incident ray MX
oblique to the interfaceAB.
4. Draw the normal NN¢ at the point of incidence Why should the pins
X. be vertical?
5. Fix two pins P & Q vertically on the incident
ray MX about 5cm apart.
6. Place the slab within the boundaryABCDA.
Ÿ Pins must be fixed 7. Looking through the opposite side of the glass
vertically. slab, fix two more pins R and S such that all the Can you predict whether a
Ÿ Use sharp pencil for
four pins appear to lie along a straight line. ray of light will bend towards
drawing work.
Ÿ The direction of the ray 8. Remove the slab and the pins. Mark and or away from the normal?
should be marked 9. encircle the pins pricks.
with an arrow head. Join R & S and extend the line upto the side CD. Let it meet CD at
Ÿ The pins should be point Y.
about 5 cm apart.
10. Join X and Y. Line XY is the refracted ray.
11. Measure the angle MXN. This is the angle of incidence i.
12. Measure the angle YXN¢. This is the angle of refraction r.
13. Using Snell's law, determine the refractive index as
n = sin i
sin r
14. Repeat the experiment two more times with different angles of
incidence.
No. of Obs. Angle of incidence Angle of refraction n = sin i
i r sin r
1
Observations
and Data
Processing
2
3
Mean refractive index = ………………………
4
Required protractor and ruler.
1. Fix the paper sheet on the drawing board with the help of thumb pins.
Procedure 2. Place a rectangular glass slab on the sheet and mark its boundary
ABCDA.
3. Remove the slab and draw an incident ray MX
oblique to the interfaceAB.
4. Draw the normal NN¢ at the point of incidence Why should the pins
X. be vertical?
5. Fix two pins P & Q vertically on the incident
ray MX about 5cm apart.
6. Place the slab within the boundaryABCDA.
Ÿ Pins must be fixed 7. Looking through the opposite side of the glass
vertically. slab, fix two more pins R and S such that all the Can you predict whether a
Ÿ Use sharp pencil for
four pins appear to lie along a straight line. ray of light will bend towards
drawing work.
Ÿ The direction of the ray 8. Remove the slab and the pins. Mark and or away from the normal?
should be marked 9. encircle the pins pricks.
with an arrow head. Join R & S and extend the line upto the side CD. Let it meet CD at
Ÿ The pins should be point Y.
about 5 cm apart.
10. Join X and Y. Line XY is the refracted ray.
11. Measure the angle MXN. This is the angle of incidence i.
12. Measure the angle YXN¢. This is the angle of refraction r.
13. Using Snell's law, determine the refractive index as
n = sin i
sin r
14. Repeat the experiment two more times with different angles of
incidence.
No. of Obs. Angle of incidence Angle of refraction n = sin i
i r sin r
1
Observations
and Data
Processing
2
3
Mean refractive index = ………………………
4
