Electricity

Question 1

What is current

Answer 1

Flow of electric charge

Question 2

What is charge

Answer 2

Unit is C and measured in coulombs

Question 3

What is Ohms Law

Answer 3

Current flowing through a conductor is proportional to the voltage across it as long as temperature stays constant.

Question 4

What is current measured by

Answer 4

Ammeter wired in series

Question 5

What is voltage measured by

Answer 5

Voltmeter wired in parallel

Question 6

What is resistance measured by

Answer 6

Ohmmeter and must be wired in series

Question 7

D.C. current

Answer 7

Flows in one direction only and comes from cells and batteries

Question 8

A.C. current

Answer 8

Flows back and forth in both directions and is used in mains electricity alternating at 50Hz

Question 9

Real current Vs conventional current

Answer 9

Conventional flows from positive to negative while real moves from negative to positive

Question 10

Series circuit

Answer 10

Wired in a row and current is the same no matter where you measure it

Question 11

Parallel circuit

Answer 11

Has a choice on the path it travels and the current will be different in each path, overall current is measured by adding up the current in all the paths

Question 12

Magnetic effect

Answer 12

Movement of charged particles in a wire disrupts a magnetic field and can be seen by placing a plotting compass over an electric wire

Question 13

Chemical effect

Answer 13

This can be seen if two ends of a circuit are placed in an electrolyte solution forming bubbles as it reacts

Question 14

Heating effect

Answer 14

This can be seen very clearly in a kettle as the metal element heats up and heats the water as current is passed through it

Question 15

Joules law

Answer 15

States that the rate of heat produced in a constant resistance conductor is proportional to the square of the current

Question 16

Metallic Conductor

Answer 16

Obeys ohms law and produces a directly proportional increase in voltage and current

Question 17

Filament bulb

Answer 17

As the bulb gets hotter with increased current the resistance increases causing it to flatten

Question 18

Semiconductor

Answer 18

Somewhere between a good conductor and a good insulator.

Question 19

Electrolyte solution

Answer 19

Active electrodes behave according to Ohms Law while inactive electrodes behave like a cell with an emf, until voltage exceeds this emf no current flows

Question 20

Vacum

Answer 20

As a low voltage is applied to a cathode it heats and emits electrons from its surface and reaches a point where all electrons are flowing