Keywords

Question 1

What is Electromotive Force (e.m.f)?

Answer 1

It is the measure of the amount of energy given to each Coulomb of charge when chemical energy in a cell is being transferred to electrical energy in a circuit.

Question 2

What is the purpose of a Cell

Answer 2

It provides the circuit with a source of energy or e.m.f

Question 3

What is the purpose of a fixed resistor?

Answer 3

Controls the amount of electric current flowing in a circuit or through or through a component

Question 4

What is the purpose of a variable resistor?

Answer 4

Controls the amount of electric current flowing in a circuit or through a component.

Question 5

What is the purpose of a fuse?

Answer 5

It is a safety device. It will either melt or blow if the current gets too high.

Question 6

What is the purpose of an Ammeter?

Answer 6

It measures the amount of electrical current flowing in a circuit or through an electrical component.

Question 7

What is the purpose of a Voltmeter?

Answer 7

Measures the size of the potential difference (e.m.f) across and electrical component

Question 8

What is the purpose of a thermistor?

Answer 8

Responds to the temperature of the environment and changes it’s resistance as a consequence.

Question 9

What is the purpose of a diode?

Answer 9

It enables current to flow in only one direction.

Question 10

What is the purpose of an LDR ( light dependant resistor)?

Answer 10

It changed the current flowing in a circuit or a component when the light intensity levels change.

Question 11

What is a conventional current?

Answer 11

When the current in a circuit flows from the positive terminal to the negative terminal

Question 12

What is Electron Flow?

Answer 12

Electrons that travel from the negative terminal to the positive terminal.

Question 13

What is Kirchoff’s first law?

Answer 13

Charges cannot be created or destroyed. The sum of charges going in must equal to the sum of charges leaving it.

Question 14

What is a coulomb?

Answer 14

It is the unit of charge (C). It is defined as the quantity of charge that passes a fixed point in one second when a current of 1 Ampere is flowing. 1C=1As

Question 15

What is the formulae for charge?

Answer 15

Charge(C)=Current(A) X Time(s)

Charge is given the symbol of Q, current it given the symbol I and time is given the symbol t.

Q=IT

Question 16

What is Ohms law?

Answer 16

V=IR Where:
V=Voltage
I=Current
R=Resistance

Question 17

What is the rate of flow of charge?

Answer 17

Current

Question 18

What is the formula for mean drift velocity?

Answer 18

V=I/(nAe)

Where
v= drift velocity
I= current
A=cross sectional area
e= charge of an electron

Question 19

What do the letters represent in the formula I=nevA

Answer 19

I=Current
v=velocity 
A=cross sectional area
n=number of free electrons
e=charge of an electron

Question 20

What is potential difference?

Answer 20

How much energy per unit charge is being transferred across a component.

Question 21

What is the formula for e.m.f. ?

Answer 21

Ę=energy transferred to charge / charge

Ę=W/Q

Question 22

What is Electric Current

Answer 22

Electric current is the rate of flow of charge. The formula is
I= Change in charge/ change in time

Question 23

What is the difference between conductors, semi conductors and insulators

Answer 23

The value of n in conductors is high

The value of n in insulators are almost 0

The value of n is somewhere in between the two