Answer:
A. The poles are opposite
Explanation:
Magnets are object that produce magnetic fields, which are regions of space that exert a forces on charged particles in motion or on other magnets.
Every magnet has 2 opposite poles, which are labelled by convention as North Pole and South Pole; the lines of the magnetic field of a magnet go out from the North Pole and go into the South Pole.
Magnetic poles always exist in pair: it means, every magnet always contains a North Pole and a South Pole. If a magnet is cut in a half, each half of the magnet will still have a North Pole and a South Pole.
Each pole exerts a force on another pole; in particular, we have:
- Like poles (north-north or south-south) repel each other
- Opposite poles (north-south) attract each other
In this problem, a magnet is attracted to a metal object: this means that the two poles must be of opposite polarity. Therefore, the correct option is
A. The poles are opposite
A covalent bond is a chemical bond which involves the sharing of atoms.
I think it is D. The National Institutes of Health found it effective in reducing pain and other symptoms, but it is not clear how it works.
<span>I believe the answer is REM alpha sleep. Sleep is a complex biological process that accompany various physiological changes. Normal sleep is usually
classified into non-rapid movement (NRE) and rapid eye movement sleep (REM),
where the stages of NREM are followed by REM sleep. REM alpha sleep is a stage of REM that is associated with unique brain wave pattern such that during REM sleep a sleepers brain waves demonstrate characteristics similar to a walking sleep, a combination of alpha, beta and desynchronous waves.</span>
