Answer:
D) electrons
Explanation:
Moving charges creates magnetic field. So the moving electrons of an atom generate microscopic magnetic field. In an atom the magnetism is destroyed when it has equal no. of electrons spinning in the opposite direction.
In the atoms of iron, cobalt and nickle there are more no. of electrons spinning in the same direction.
-- transport of energy
-- wavelengths equal to their speed divided by their frequency
-- frequencies equal to their speed divided by their wavelength
-- periods equal to the reciprocal of their frequency
-- speeds that are determined by the characteristics of the medium
Answer:
7revolutions
Explanation:
Given parameters:
Initial revolution = 250rpm
Final revolution = 150rpm
Time = 4.2s
Unknown:
Number of revolutions that occur at this time = ?
Solution:
To solve this problem;
let us find the change in revolution = 250rpm - 150rpm = 100rpm
Convert the time to seconds;
60s makes 1 minute
4.2s will make 
= 0.07min
So;
The number of revolutions at this time = 100rpm x 0.07min
= 7revolutions
That is a vector. It is a combination of direction and velocity. (You can think of Vector from Despicable Me to help you remember the term)
:)
