Physics - Waves questions Watch
2. An oscillator is used to send waves along a streched cord. The cord is 20cm long, and four complete waves fit along its length when the oscillator vibrates 30 times per second. For the waves on the string:
a) what is their wavelength?
b) what is their frequency?
c) what is their speed?
Think of a huge sphere surrounding the sun, with its radius as the distance to the Earth.
The surface area of this sphere = 4π x (150^9)^2
= 2.83 x 10^23 m^2
We know that, at the distance of the Earth from the Sun, the intensity of radiation is 1370 W per square metre.
Therefore, total power output = 1370 x (2.83 x 10^23)
= 3.88 x 10^26 W
b) 30 "times per second" = 30 Hz
c) v = f.lambda = 5 * 30 = 150 cm/s = 1.5 m/s
Thanks 4 help ppl.