ELECTROMAGNETISM

Question 1

magnetic field

Answer 1

an area in which a magnetic object experiences a magnetic force

Question 2

magnetic field line

Answer 2

an imaginary line representing a magnetic field

Question 3

characteristics of magnetic field

Answer 3

1. is a plane perpendicular to the current carrying conductor
2. is the strongest close to the conductor , therefore the magnetic field lines are closer together near the wire
3. direction in which a compass needle points(N Pole) is the direction of the magnetic field at that point
4. direction of the current is reversed, the direction of the magnetic field is also reversed
5. magnetic field is continuous
6. is 3D

Question 4

RHR for straight current carrying conductor

Answer 4

if the thumb points in the direction of the conventional current, the curled fingers will point in the direction of the magnetic field around the conductor

Question 5

RHR for a solenoid

Answer 5

if the curled fingers point in the direction of the conventional current, the thumb will point to the north pole of the induced magnetic field in the solenoid

Question 6

advantages of overhead cables

Answer 6

1. much cheaper than underground cables
2. its easier to determine faults and breaks
3. maintenance is easier and cheaper

Question 7

disadvantages of overhead cables

Answer 7

1. can easily be stolen

Question 8

what happens to magnetic flux if a magnet moves into a solenoid

Answer 8

the magnetic flux increases at the entrance of the solenoid

Question 9

magnetic flux density

Answer 9

magnetic field strength.

Question 10

symbol and unit of measurement for magnetic flux density

Answer 10

1. B

2. tesla(T)

Question 11

when is magnetic field very strong

Answer 11

when the magnetic field lines are close together it indicates that magnetic flux is great and the magnetic field is very strong

Question 12

magnetic flux

Answer 12

the product of the component of magnetic flux density, perpendicular to the loop, and the area enclosed by the loop

Question 13

symbol and unit of measurement of magnetic flux

Answer 13

1. phi

2. weber(Wb)

Question 14

faradays law

Answer 14

the magnitude of the induced emf across the ends of a conductor is directly proportional to the rate of change in the magnetic flux linkage with the conductor

Question 15

what does the magnitude of the induced emf in the conductor depend on

Answer 15

1. area covered by the magnetic field
2. strength of magnetic field
3. rate of change of the magnetic flux
4. number of turns in the solenoid