A large water tank is set up so that a wave can be generated at each end of the tank. The two waves, A and B, travel towards each other at the same speed.
The graph shows the variation of displacement of the water surface with distance travelled at a particular instant.
(a)
Deduce how many times greater the amplitude of B is to the amplitude of A.
Two microwave transmitters are placed 15 cm apart and connected to the same source. A receiver is placed 70 cm away and moved along a line parallel to the transmitters. The receiver detects and alternating pattern of maxima and minima.
One transmitter is removed and a metal grille is placed between the transmitter and the receiver. The grille is rotated through 180o and back round again. The signal at the receiver is heard to rise and fall as the grill rotates.
(d)
(i) Explain what causes the rising and falling signal.
[2]
(ii) Sketch a graph to show the pattern of rising and falling signal.
The analyser is used to investigate polarised light. Light with intensity 11.94 W m−2 is incident on a polarising filter. The transmission axis of the analyser is fixed at an angle of 35º to the electric field of the polarised light.
(c)
(i) Write down the intensity of the light transmitted by the polarising filte
[1]
(ii) Calculate the intensity of the light transmitted by the analyser
A microwave transmitter is set up 75 cm away from a receiver which is connected to an oscilloscope so that the intensity of the wave incident on the receiver can be determined.
Initially the intensity is found to be 32 mW m−2. The receiver is moved to a new position 125 cm from the transmitter. The new intensity is found to be 11.6 mW m−2.
(a)
Show that these results support the theory that intensity is related to distance according to an inverse square law.
Radio waves are emitted from a straight conducting rod antenna such that the plane of polarisation of the waves is parallel to the rod. An identical metal conducting rod, known as an aerial, is used for reception.
(c)
Suggest why the receiving aerial must be set up parallel to the transmitting antenna.
A group of hikers are exactly equidistant between two radio transmitters, X and Y. The transmitters are set to an operating wavelength of 200 m and have the same power outputs.
(a)
The hikers at point P receive a signal with zero amplitude. Outline what information about the signal you can assume from this.
