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1)Microwaves are directed normally at a plane metallic reflector. A detector moving along the normal to the reflector travels 15 cm from the first to the 11th successive of minimum intensity. What is the frequency of the microwave?(velocity of microwaves = 3 x 10^8 m/sec)

I solved it in the following way:

The incident and the reflected microwaves superimpose to produce standing waves. The distance between the first and the 11th minimum is given that it is 15 cm.

Therefore,

0.15 = 10 x (lambda/2)

Lambda = 0.03 meters

Frequency = (3 x 10^8)/ 0.03

= 10^10 Hz

Is it right?

2)Two waves of same frequency travel in opposite directions in a medium with amplitudes 3 units and 2 units respectively. What is the ratio of the amplitudes at an antinode and a node in the stationary wave?

I think it is infinity because at the antinode it has maximum amplitude and at the node it is zero. Is it right?

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# Homework Help: Frequency of microwaves

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