Principles Of Electrical Science

Question 1

What are the 2 main parts of an atom?

Answer 1

The nucleus and the electron cloud

Question 2

Which part of an atom has a negative charge?

Answer 2

The electron

Question 3

Which part of an atom has a positive charge?

Answer 3

Proton

Question 4

In electron current theory, in which direction do the electrons flow?

Answer 4

From the negative terminal through the conductor to the positive terminal

Question 5

What is the charge state of an atom with an extra electron?

Answer 5

Negatively charged

Question 6

What is conventional current flow?

Answer 6

The flow of electrons from negative to positive

Question 7

State three effects of an electric current

Answer 7

Thermal effect
Chemical effect
Magnetic effect

Question 8

What is the smallest atom?

Answer 8

Hydrogen

Question 9

What is the heaviest atom?

Answer 9

Uranium

Question 10

What is the unit of electric current?

Answer 10

Ampere

Question 11

True or False: Voltage is the measure of electric potential difference.

Answer 11

True

Question 12

Fill in the blank: The formula for Ohm’s Law is ________.

Answer 12

V = IR

Question 13

What does the symbol ‘R’ represent in electrical equations?

Answer 13

Resistance

Question 14

What is the SI unit of resistance?

Answer 14

Ohm

Question 15

Which law states that the current through a conductor between two points is directly proportional to the voltage across the two points?

Answer 15

Ohm’s Law

Question 16

What is the relationship between power (P), voltage (V), and current (I)?

Answer 16

P = VI

Question 17

True or False: Direct current (DC) flows in one direction only.

Answer 17

True

Question 18

What type of current alternates direction?

Answer 18

Alternating current (AC)

Question 19

What is the unit of electrical power?

Answer 19

Watt

Question 20

Multiple Choice: Which of the following is a conductor? A) Rubber B) Copper C) Wood

Answer 20

B) Copper

Question 21

What is capacitance?

Answer 21

The ability of a system to store an electric charge.

Question 22

What is the unit of capacitance?

Answer 22

Farad

Question 23

Fill in the blank: The energy stored in a capacitor can be calculated using the formula ________.

Answer 23

E = 1/2 CV^2

Question 24

What does an inductor do in a circuit?

Answer 24

Stores energy in a magnetic field.

Question 25

True or False: Resistance is independent of temperature.

Answer 25

False

Question 26

What is Kirchhoff's First Law?

Answer 26

The sum of currents entering a junction must equal the sum of currents leaving the junction.

Question 27

What is the formula for calculating total resistance in series circuits?

Answer 27

R_total = R1 + R2 + R3 + ...

Question 28

What is the formula for calculating total resistance in parallel circuits?

Answer 28

1/R1 + 1/R2 + 1/R3 so on

Question 29

What is the main purpose of a fuse in an electrical circuit?

Answer 29

To protect the circuit from overcurrent.

Question 30

Fill in the blank: The relationship between frequency (f) and period (T) is ________.

Answer 30

f = 1/T

Question 31

What is the principle of electromagnetic induction?

Answer 31

A changing magnetic field can induce an electric current.

Question 32

True or False: A transformer can increase or decrease voltage levels.

Answer 32

True

Question 33

What type of circuit provides multiple paths for current to flow?

Answer 33

Parallel circuit

Question 34

What is the primary function of a resistor in a circuit?

Answer 34

To limit the electric current.

Question 35

Multiple Choice: Which of the following is a semiconductor? A) Silicon B) Copper C) Gold

Answer 35

A) Silicon

Question 36

What is the equation for resistance in a circuit?

Answer 36

Volts / amp

Question 37

What is the SI unit of temperature?

Answer 37

Kelvin

Question 38

What would a 2.5sq/mm twin and earth cable would usually be used for?

Answer 38

A domestic ring circuit

Question 39

What is the 'constant' for RMS values?

Answer 39

0.707

Question 40

What is the name of the insulating medium used in a MI cable?

Answer 40

Magnesium oxide

Question 41

What is the main purpose of 'equipotential bonding' ?

Answer 41

To maintain all exposed metal work at the same potential

Question 42

What is the formula for work done?

Answer 42

Force x distance

Question 43

What is the formula for resistance in a circuit?

Answer 43

Volts / ampere

Question 44

If current in a circuit remained constant and voltage increased the resistance of the circuit would….

Answer 44

Increase