Week 1

Question 1

What are the 4 basic elements of an electrical circuit?

Answer 1

source
load
switch
conductors

Question 2

What is a source in an electric circuit?

Answer 2

a source that delivers electricity, eg. generators, batteries, alternators

Question 3

What is a load in an electric circuit?

Answer 3

A load that consumes the supplied electricity, e.g., light bulbs, motors, relays etc.

Question 4

What is a switch in an electric circuit?

Answer 4

A switch that controls the “on” and “off” of the load

Question 5

What is a conductors in an electric circuit?

Answer 5

Connecting conductors

Question 6

What are 4 circuit symbol sources in an independent source?

Answer 6

dc voltage source
ac voltage source
battery
current source

Question 7

What are 2 circuit symbol sources in an dependent source?

Answer 7

Dependent voltage source

dependent current source

Question 8

What is a current?

Answer 8

Electric current (i) is defined as the rate at which charge (q) flows through a surface (for example, the cross section of a wire)

Question 9

Is current measured through or across an element?

Answer 9

Current is always measured through an element

Question 10

What is a voltage?

Answer 10

Voltage (v), also called electromotive force, is the potential difference in charge between two points in an electrical field

Question 11

Is voltage measured through or across an element?

Answer 11

Voltage is always measured across an element

Question 12

What is resistance?

Answer 12

The resistance (R) of a material is the property to resist the flow of charges when an external electric field is applied

Question 13

What is resistance of a material depend on?

Answer 13

Resistance of a material depends on its length (l), cross sectional area (A)
and the resistivity of the material (p)

Question 14

What is Ohm’s law?

Answer 14

At a given temperature, the current through a conductor (I) between two points is directly proportional to the potential difference (V) between those two points. The proportionality constant depends on the resistance (R) between the two points

Question 15

What is the direction which conventional current flow go?

Answer 15

Clockwise

Conventional current flow direction is same as the direction of positive charges

Question 16

What is the direction which electron flow go?

Answer 16

Anticlockwise

Question 17

What is electrical power?

Answer 17

Rate of energy absorbed or produced within the circuit

Question 18

What is electrical energy?

Answer 18

Electrical power within a circuit consumed over a period of time

Question 19

What is a series circuit?

Answer 19

Any electric circuit having all elements joined in a sequence such that the same current flows through them all. Voltage across the circuit is the sum of the voltages across each element

Question 20

What is a parallel circuit?

Answer 20

In a parallel circuit both terminals of an element are respectively connected to each terminal of the other element or elements. Voltage across each element is the same and the total current is the sum of the currents through each element

Question 21

What is kirchoff’s current law?

Answer 21

The sum of the currents entering a junction of a network is equal to the sum of the currents leaving the same junction

Question 22

What is the sum of voltages difference across a closed loop network equal to?

Answer 22

∑ V = 0 for a closed loop

Question 23

What direction, voltage polarity is a closed loop?

Answer 23

In this circuit, the current is assumed to be in the clockwise direction. Then the voltage polarities across each resistor will be as shown. The current entering end of a resistor will have a positive (+) polarity and the leaving end will have a negative (-) polarity

Question 24

What are ammeters connected by, series or parallel?

Answer 24

Ammeters are always connected in series so that the current to be measured should go through it. They have a negligible internal resistance, Hence the magnitude of the current will not change due to the insertion of an ammeter when it is connected in series

Question 25

What is the voltage and resistance and what will happen to the current in an open circuit?

Answer 25

• No current will go through the open circuit between a and b
• Resistance across a and b is very high (infinity)
• Voltage across a and b depends on the other elements in the circuit and it will not be zero

Question 26

What is the voltage and resistance and what will happen to the current in an short circuit?

Answer 26

• Voltage across a and b is zero, Vab = 0
• There will be a current going through the short circuit between a
  and b
  - Resistance across a and b is zero