Power/ Magnetism

Question 1

What are the components in a HRC FUSE LINK

Answer 1

Quartz powder, fuse wire, casing

Question 2

Key parts in a Cartridge fuse?

Answer 2

End caps, Fuse wire, Transparent casing

Question 3

What’s the Power Triangle initials?

Answer 3

PIV 
                       /      \
                    /           \
                 /       P       \
              / ——— ——\
            /        I         V     \
          ————————

Question 4

What is the unit of electrical power?

Answer 4

Watts

Question 5

How many watts make one horsepower?

Answer 5

746

Question 6

Complete the following;
When an HRC fuse blows, the _____ powder ______ and fills the gap between the two ends of the fuse ______. Quartz is an _____ , so now no ______ is possible.

Answer 6

When an HRC fuse blows, the quartz powder melts and fills the gap between the two ends of the fuse wire. Quartz is an insulator, so now no arc is possible.

Question 7

Why is all electrical equipment earthed to the hull of the ship?

Answer 7

For safety to prevent a possible lethal electrical shock.

The ships hull has zero earth potential

Question 8

What three things can cause an earth fault in a circuit?

Answer 8

Dampness, Brittle or hard insulation caused by heat or age, accidental damage.

Question 9

What is the electrical potential of the sea?

Answer 9

0 volts

Question 10

Name two types of fuses?

Answer 10

Cartridge fuse and High rupturing capacity fuse. (HRC)

Question 11

What is the name of the naturally magnetic iron ore

Answer 11

Magnetite

Question 12

There are lines of force that pass through the space surrounding a magnet, what are these lines called?

Answer 12

Lines of magnetic Flux

Question 13

What direction do the lines of magnetic flux travel?

Answer 13

They leave the magnet at the North Pole and re-enter at the South Pole

Question 14

Name 2 types of commonly used permanent magnets.

Answer 14

Bar and horseshoe

Question 15

What happens if 2 like poles are brought close together?

Answer 15

There will be a force of repulsion, pushing them apart.

Question 16

What happens if 2 un-like poles are brought together?

Answer 16

There will be a force of attraction, pulling them together.

Question 17

List 3 materials that, mixed with steel, will produced stronger magnets

Answer 17

Nickel, aluminium, cobalt.

Question 18

What is produced around a conductor when a current is passed through it?

Answer 18

Lines of magnetic flux

Question 19

Permanent magnet and electro- magnet are two ways of producing a magnet. Name one more.

Answer 19

Stroking a permanent magnet along a magnetic material.

Question 20

Select all the requirements needed for magnetism to produce a voltage by induction.

Answer 20

An electrical conductor, a magnetic field, relative movement.