Physics electricity

Question 1

Charge is measured

Answer 1

is measured in Coulombs (C).

Question 2

Charge symbol

Answer 2

Q

Question 3

electron charge

Answer 3

One electron has a charge of 1.6x10-19 C.

Question 4

1 Coulomb

Answer 4

is defined as the amount of charge that passes in 1 second when the current is 1 Ampere

Question 5

Current (I)

Answer 5

is the rate of flow of charge, and is measured in Amperes (A).

A current of 1A means that 1 coulomb of charge flows past that point every second (hence the term “rate”).

Question 6

current symbol

Answer 6

I in equation

Question 7

current flow equation

Answer 7

Therefore I=dQ/dt, or more simply, I=Q/t.

Question 8

Potential Difference (Voltage, V)

Answer 8

is measured in volts (V), and is the work done per unit charge.

1V means that 1 Joule of work is done in pushing 1 coulomb of charge through a particular area/component.

Question 9

Voltmeters are placed in parallel and have infinite resistance,

Answer 9

Voltmeters are placed in parallel and have infinite resistance, so they measure current between 2 points in a circuit.

Question 10

volt equation

Answer 10

V=WQ=EnergyCharge

Question 11

Resistance (R)

Answer 11

is difficult to define, but is measured in Ohms (Ω).

Some people call it the ratio of voltage to current, which is a pretty obvious definition when you consider Ohm’s Law, which we all know:

Question 12

Resistance (R) equation

Answer 12

r=v/;i

v=ir

Question 13

Power (P) is measured in watts (W)

Answer 13

and is defined as the rate of transfer of energy.

1W is the transfer of 1 Joule of energy per second.

Question 14

There are two basic formulae for power that you need to know.

Answer 14

P=ET
P=IV
P=I^2R
P=V^2R

Question 15

Energy

Answer 15

E=ItV