Electric fields are produced by two kinds of charges, positive and negative. Magnetic fields are associated with two magnetic poles, north and south, although they are also produced by charges
Answer:
A compass needle points north because the north pole of the magnet inside it is attracted to the south pole of Earth's built-in magnet. Now if the needle in your compass is pointing north, that means it's being attracted (pulled toward) something near Earth's north
Explanation:
If the distance between you and the source is increasing, then
you'll hear a sound with a lower pitch than the sound the source
is actually making. Either you're moving away from the source,
or the source is moving away from you.
Ultraviolet radiation from the sun is controlled by the ozone but if it infiltrates into the atmosphere it becomes a hazard. The uv reaches our eyes and darkens the retina and blurs vision. The fovea becomes insensitive and the cells dormant. This causes gradual blindness.