Mantle I think idrk cuz of erosion
Set up a proportion
1 mile/1.6 km = 20,000miles/x
Cross Multiply
x = (20,000) * (1.6)
x = 32,000 kilometers
Answer:
An element is a pure substance and is made of only one type of atom; it cannot be broken down into a simpler substance.
The relationship between frequency and wavelength for an electromagnetic wave is

where
f is the frequency

is the wavelength

is the speed of light.
For the light in our problem, the frequency is

, so its wavelength is (re-arranging the previous formula)
Taking the copper wire, he has to wind it around the nail made of iron. After which, he then connect both ends of the copper wire to the battery, so an electric charge travels through the wire. This is the basic electromagnet. Since a current is now flowing through the wire, a magnetic field is produced. Placing the electromagnet near the mixture of copper and iron, the magnet should attract the pieces of iron, as iron is more magnetic compared to copper. This is done over a period of time, so that only the copper pieces are left in the mixture.