A note was played on a a keyboard. The frequency of the note was 440 Hz. (a) What does a frequency of 440 Hz mean? (b) The sound waves produced by the keyboard travel at a speed of 340 m/s. Calculate the wavelength of the note.
(a) A frequency of 440 Hz means that a single trough and peak of the sound wave oscillates 440 times per second or equally that 440 sound waves are produced by the keyboard per second (This is because the SI unit of a Hz is inverse seconds s^-1)
(b) We first need the equation that relates the two given quantities we have (wave velocity and frequency) to the third unknown, desired quantity (wavelength). This is equation is a simple one, v = f lambda. We want the quantity lambda, so we have to divide both sides of the equation by f to get v / f = lambda. We then plug in the numbers to find lambda, the wavelength, which is lambda = 340 m /s / 440 /s = 340/440 m (as the /s units cancel out leaving just length which is the correct unit for a wavelength!)
Related Physics GCSE answers
All answers ▸(IGCSE, Jan 2013, q8 adapted) The astronaut David Scott dropped a hammer and a feather from rest, at the same time and from the same height on the moon. The hammer and the feather landed at the same time. Why?
Two beakers contain water at room temperature. One contains 200ml, the other 400ml. If both beakers are heated above identical Bunsen burners, which of the two will take longer to boil?
A rollercoaster carriage of mass 100kg has 45kJ of Kinetic Energy at the lowest point of its ride. Ignoring air resistance and friction between the wheels and the tracks, what is the maximum height above this point it could reach? [Take g as 10m/s/s)
Imagine a probe in space. Argon gas can be fired from the probes fuel tanks to propel the probe. Discuss whether conservation of momentum applies and whether the speed of the probe increases.