UNIT 5

Question 1

magnets can occur … or can be …

Answer 1

naturally , man-made

Question 2

what is a magnet

Answer 2

an object that can attract other objects containing iron, cobalt, or nickel

Question 3

give exemple of naturally occuring magnetic material mineral

Answer 3

Magnetite composed of iron and oxygen

Question 4

what makes a magnet magnetic

Answer 4

DOMAINS (aka the arrow sections)

Question 5

when is a substance magnetized

Answer 5

when the domains allign (aka the arrows point in the same direction)

Question 6

what creates tiny magnetic fields

Answer 6

the spin of the electrons (since each domain is made up of many atoms)

Question 7

what is a ferromagnetic substance

Answer 7

a substance with the ability to acquire magnetic properties

Question 8

all magnets have a … and a… even if you

Answer 8

NORTH , SOUTH (even if you break it in two)

Question 9

oposite poles …
same poles…

Answer 9

oposite poles attract
same poles repel

Question 10

describe magnetic field?

Answer 10

the space around the magnet hwere the magnetic force of a magnet can be felt

Question 11

what does NO SIN stand for

Answer 11

North Out South IN (so the arrows point out for north and in for south)

Question 12

always … to …

Answer 12

north to south

Question 13

what determines the strength of the magnetic field

Answer 13

the closer the lines are together, the stronger the field

Question 14

explain compasses

Answer 14

• it points towards the Earth’s geographic North
• but it actually points towards the Earth’s magnetic South

Question 15

describe how to use the right hand rule

Answer 15

• conventional current goes + to - so point your thumb towars - (aka away from positive)
• then your fingers wrap in the direction of the magnetic field

Question 16

current intensity can

Answer 16

(the rate of electron flow) can generate a magnetic field

Question 17

what is a solenoid?

Answer 17

a cylindrical coil of live wire

Question 18

a solenoi is … so it acts like a…

Answer 18

coiled, bar magnet

Question 19

describe how the OTHER right hand rule works for solenoids?

Answer 19

• first wiht your right hand wrap your finger in the direction of the conventional current (aka the way the wires coil)
• then your thumb is pointing to the direction of the NORTH pole of the magnet

Question 20

3

how can the power of an electromagnet be increased

Answer 20

1. using a ferromangetic core with a lower magnetic remenance
2. increasing the current intensity
3. adding more loops

Question 21

what does having low remenance mean

Answer 21

its domains can easily be alligned (so they lose their alignment very easily)

Question 22

3

explain the use of solenoids in technological applications

Answer 22

1. the magnetic field can be switched on or off
2. the direction of the magnetic field can be easily switched
3. the intensity of the magnetic field can be modified (raise/lower the current intensity or add/emove loops)

Question 23

solenoid can be transformed into what and how

Answer 23

electromagnets (by inserting a ferromagnetic core inside)

Question 24

exemples of what solenoids are in

Answer 24

vending machines, printer, syringe pumps, door bell and locks, washing machines

earphones, electric motor, magnetic crane