Answer:
Wavelength of the sound wave that reaches your ear is 1.15 m
Explanation:
The speed of the wave in string is

where T= 200 N is tension in the string ,
=1.0 g/m is the linear mass density


Wavelength of the wave in the string is

The frequency is

The required wavelength pf the sound wave that reaches the ear is( take velocity of air v=344 m/s)

Answer:
a
Explanation:
b, c, and d are all opinion based, a is the only one that you need factual evidence and observations.
The first step would be to create an electromagnet. You can create an electromagnet by winding a copper wire around the nail, the connect both ends to the battery. A current would start flowing around the nail through the wire, creating an electromagnet with its own magnetic field. Next, bringing the electromagnet to the mixture of copper and iron would slowly attract the pieces of iron (as copper is weakly magnetic). Do this slowly and the iron pieces would all slowly be separated from the copper pieces.