Electrons and Electricity

Question 1

What are the 2 types of current?

Answer 1

Direct current (DC) and Alternating current (AC)

Question 2

What is current?

Answer 2

The flow of electrons caused by a potential difference

Question 3

Describe the flow of electrons in direct current?

Answer 3

In direct current the electrons flow in one direction through a conductor.

Question 4

Describe the flow of electrons in alternating current?

Answer 4

In alternating current the electrons change direction back and forth in the conductor.

Question 5

What is a source of D.C.?

Answer 5

Chemical cells and batteries

Question 6

What’s a source of A.C. ?

Answer 6

Mains electricity

Question 7

Alternating current definition

Answer 7

A current which changes direction and instantaneous value with time

Question 8

What is the AC equivalent of DC voltage and current?

Answer 8

The root mean squared (Vrms/Irms)

Question 9

Do you used peak or rms in ohms law calculations surrounding AC/DC supplies?

Answer 9

rms values

Question 10

What equipment do you use to measure the frequency and peak voltage of an AC supply?

Answer 10

An oscilloscope

Question 11

What the DC equivalent of a 2Vrms AC supply?

Answer 11

2V

Question 12

EMF definition

Answer 12

The electromotive force is the number of joules of electrical energy given to each column of charge that passes through the source

Question 13

What is a property of an ideal cell?

Answer 13

One without internal resistance

Question 14

What are lost volts?

Answer 14

The potential difference developed across the internal resistance of a cell in a circuit

Question 15

What is the terminal potential difference?

Answer 15

The potential difference across all over terminals in a circuit

Question 16

The larger the current, the ______ the value of lost volts and the ________ the terminal potential difference

Answer 16

Higher, Lower

Question 17

What is Vlost when the current is zero?

Answer 17

V lost is 0

Question 18

What is the terminal potential difference when current is zero?

Answer 18

Equal to the EMF of the battery/cell

Question 19

What is an open circuit?

Answer 19

A circuit where no current is flowing (and it’s terminal voltage is equal to EMF)

Question 20

What is a short circuit?

Answer 20

When there is only the voltage supply in a circuit (so current and Vlost is maximum)

Question 21

What is the gradient of a voltage/current graph equal to?

Answer 21

The negative of the internal resistance (m = -r)

Question 22

What is a capacitor?

Answer 22

An electronic device that can store charge and energy in a DC circuit

Question 23

What is the relationship between charge stored and potential difference in a capacitor?

Answer 23

The charge stored is proportional to the potential difference

Question 24

How do we find the energy stored in a capacitor using a change-potential difference graph?

Answer 24

By calculating area under the graph as it is equal to the energy stored

Question 25

What happens to the current in a capacitor circuit when the capacitor is being discharged?

Answer 25

The current flows in the opposite direction going from - Imaximum to 0

Question 26

How can you increase the charging time of a capacitor?

Answer 26

Increasing the resistance of the circuit will limit the size of the current, slowing down charging