Download electricity : answer key

ELECTRICITY : ANSWER KEY
SECTION REVIEW 2-1
1. A MAGNETIC FIELD, REPRESENTED BY LINES OF FORCE EXTENDING
FROM ON PLE OF A MAGNET TO THE OTHER, IS AN AREA OVER WHICH THE
MAGNETIC FORCE IS EXERTED.
2. LIKE POLES REPEL EACH OTHER, AND UNLIKE POLES ATTRACT.
3. THE FORCE OF ATTRACTION OR REPULSION OF A MAGNETIC MATERIAL
DUE TO THE ARRANGEMENT OF ITS ATOMS – PARTICULARLY ITS
ELECTRONS.
4. A REGION IN WHICH THE MAGNETIC FIELDS OF INDIVIDUAL ATOMS ARE
GROUPED TOGETHER, IN MAGNETIZED MATERIAL, THE MAGNETIC
DOMAINS ARE ALIGNED IN THE SAME DIRECTION, WHEREAS IN
UNMAGNETIZED MATERIAL, THE MAGNETIC DOMAINS ARE ARRANGED
RANDOMLY.
SECTION REVIEW 2-2
1. THE EARTH EXERTS MAGNETIC FORCES ON MAGNETS AND COMPASSES
AND IS SURROUNDED BY A MAGNETIC FIELD.
2. THE EARTH’S MAGNETIC FIELD EXERTS A FORCE ON THE MAGNETIZED
COMPASS NEEDLE, CAUSING IT TO LINE UP IN A NORTH-SOUTH
DIRECTION.
3. THE NORTH POLE OF A MAGNET IS ATTRACTED TO THE GEOGRAPHIC
NORTH POLE OF THE EARTH. BECAUSE OPPOSITE POLES ATTRACT, THE
GEOGRAPHIC NORTH POLE N\MUST ACTUALLY BE A MAGNETIC SOUTH
POLE.
4. THE ERROR IN A COMPASS CAUSED BY THE DIFFERENCE IN LOCATION
BETWEEN THE EARTH’S MAGNETIC AND GEOGRAPHIC POLES.
5. SUNSPOTS ARE VERY STRONG MAGNETIC FIELDS WITHIN CERTAIN
REGIONS OF THE SUN. THE OCCURRENCE OF SUNSPOTS IS BELIEVED TO
BE RELATED TO VARIATIONS IN THE SUN’S MAGNETIC FIELD.
SECTION REVIEW 2-3
1. NO FORCE IS EXERTED ON A CHARGED PARTICLE MOVING IN THE SAME
DIRECTION AS A MAGNETIC FIELD. A MAGNETIC FORCE WILL CAUSE
CHARGED PARTICLES MOVING AT AN ANGLE TO A MAGNETIC FIELD TO
MOVE IN A SPIRAL AROUND THE MAGNETIC-FIELD LINES.
2. IT TRAPS CHARGED PARTICLES AND FORCES THEM TO SPIFAL AROUND
THE MAGNETIC-FIELD LINES, THUS PREVENTING THEM FROM REACHING
THE EARTH’S SURFACE.
3. THE VAN ALLEN RADIATION BELTS ARE TWO LARGE REGIONS WHERE
MOST CHARGED PARTICLES ARE FOUND IN THE MAGNETOSPHERE. WHEN
A LARGE NIMBER OF CHARGED PARTICLES IN THE BELT GET CLOSE TO
EARTH, THEY COLLIDE WITH PARTICLES IN THE ATMOSPHERE. THE
COLLISION CAUSES THE AURORA.
4. THE MAGNETIC FIELDS MAY BE USED TO CREATE A MAGNETIC BOTTLE
THAT COULD CONTAIN PARTICLES FOR FUSION AT THE REQUIRED
TEMPERATURES.