Higher Physics Lab Light & Optics



Exp-1 To determine the speed of light in air.

  • 1MHz internal modulation frequency.
  • Dual channel photo detector.
  • Speed of light.
  • Internal modulation.
  • Laser beam.
  • Peak difference.
  • Path difference.

Principle and Working :
The LASER beam from the transmitter strikes the beam splitter to split the beam in two perpendicular directions. The first beam is transmitted through transmitter directly and is received in first channel of the receiver. The second perpendicular beam from beam splitter travels a larger distance by being reflected back from a mirror placed about 5 meter or more and is received in second channel of the receiver.
In the present setup, the time difference between the two peaks of received LASER signals can be observed on a oscilloscope (>40MHz) and can be used to calculate the speed of light.


Cat. No. Item Name Qty
CD818 Laser transmitter module 1
CD819 Laser receiver module 1
R7950 Power adaptor 5V 2
CD820 Beam splitter 1
SL752 Convex lens f=50mm 2
SG110 Cylindrical base 5
C821 Reflecting mirror in mount 1
SG101 'A' base 1
SG038 Support rod 1
C7659 BNC to BNC cable 2

* Additionally Required

Oscilloscope >40MHz is not supplied with the setup.

Light & Optics Experiments