7c

Question 1

Circuit breaker
Earth wire

Answer 1

Safety device that opens a resettable switch, causing a break in a electric circuit when too much current flows through it
Provides low resistance path for current to flow from inside of appliance to the ground in order to avoid electric shock

Question 2

Electric shock
Fuse

Answer 2

Sensation and damage done when electrical currents flow through a person or living thing
Safety device that melts when to much current flows through it causing a break in a circuit

Question 3

Load
Short circuit

Answer 3

Amount of electrical energy consumed (in the form of current) by a Transductor,
Situation in which current flows through an unintended path with lower resistance causing accidental contact between components

Question 4

Residual current device (rcd)

Answer 4

Safety switch that switches of a household electric circuit when it detects a difference between the current flowing through and active wire and neutral wire

Question 5

How do fuse operate as a weak point

Answer 5

Form part of a circuit preventing overheating by stopping current form exceeding a value.
- current flows through wire produce heat
- thinner wire greater heat produced
Fuse gets hotter then circuit melting and breaking circuit.

Question 6

Circuit breakers opening the circuit

Answer 6

Prevent damage and fire
They trip not melt with easy reset good for homes
It is in a circuit distrubutjon board if current surge is detected electricity will only stop flowing tot he part of the building that are effected
Current exceeds rate value it opens the circuit, due to bimetallic strips generating heat and conducting electricity. If current is to high metal expands bimetallic strip bending via a pivotal mechanism disconnecting circuit.

Question 7

How can earth wire prevent electric shock

Answer 7

Prevent current flow to wrong place
Prevent active wire contacting external appliance and causing shock, provide connection to metal exterior to the ground. Current follow path of least resistance (short circuit) directing current to earth wire with less resistance then human.

Question 8

How does risidual current create open circuit

Answer 8

Breaks circuit when current flow to wrong place for circuit breaker and fuse, prevent electric shock(where current flows through person instead of neutral wire person being lower resistance path) by
1. Current flows wrong direction in active and neutral wire
2. Magnetic field produced when current flows through wire
3. When current flows through wrong direction opposing man
Genetic fields are produced
4. Opposing magnetic fields cancel eachotehr out so no overal magnetic field exists in the sensor
5. Sensor switch allows current to flow throughout the circuit

• recognises difference in current triggering circuit to open

Question 9

Electric shock

Answer 9

100-500ma can cause heart beta irregulars persisting longer than shock, called ventricular fibrillation
5000ma 5a cause heart to contract for shock duration, long period is fatal short cna help defibrillate
.1 s harsh current is fine as well as low current