You hear 2 beats per second when two sound sources, both at rest, play simultaneously. The beats disappear if source 2 moves toward you while source 1 remains at rest. The frequency of source 1 is 500 Hz. The frequency of source 2 is...

A) 498 Hz.

B) 496 Hz.

C) 502 Hz.

D) 500 Hz.

E) 504 Hz.

Option A

498 Hz

Explanation:

Beat frequency is given by F1-F2 where F is the frequency of source while F2 is frequency that disappear as one moves towards the source. when a source moves towards observer the frequency increases

Substituting 500 for F1 and 2 for F2 then

Beat frequency is 500-2=498 Hz

Option A

a.metals can become magnetic if they have many spinning electrons that create magnetic fields.d.only some metals are attracted by magnets; these metals are called ferromagnetic.

d.wrapping an insulated wire around a metal with ferromagnetic properties and applying an electric current.