Science - Energy and Electricity

Question 1

What is electrical energy?

Answer 1

Electrical energy allows for the transfer of energy quickly and efficiently from one place to another, transforming into various forms to do useful work.

Question 2

Define an electrical circuit.

Answer 2

An electrical circuit is a closed loop that makes use of a flow of electrons, consisting of a supply of electrons, conductors, and components that require electrical energy.

Question 3

What is a conductor?

Answer 3

A conductor is a material that allows electricity to flow through it, such as metal.

Question 4

What is an insulator?

Answer 4

An insulator is a material that does not allow electricity to flow through it, such as wood or plastic.

Question 5

What is the difference between conventional current and electron flow?

Answer 5

Conventional current flows from the positive terminal to the negative terminal, while electron flow moves from the negative terminal to the positive terminal.

Question 6

Fill in the blank: Conventional current flows from _________ to negative.

Answer 6

positive terminal

Question 7

Fill in the blank: Electrons are flowing from ___________ to ___________.

Answer 7

negative terminal, positive terminal

Question 8

What are the main components of an electrical circuit?

Answer 8

• Power supply
• Conducting wires
• Components needing electricity

Question 9

What is a series circuit?

Answer 9

A series circuit is a circuit with all components connected in a single loop.

Question 10

What is a parallel circuit?

Answer 10

A parallel circuit has components connected in different loops.

Question 11

What happens to bulb brightness in a series circuit as more bulbs are added?

Answer 11

The brightness decreases as more bulbs are added in series.

Question 12

What happens to bulb brightness in a parallel circuit as more bulbs are added?

Answer 12

The brightness remains the same as more bulbs are added in parallel.

Question 13

What is the formula for current?

Answer 13

Current (I) is measured in Amperes (A) using an ammeter.

Question 14

What is the formula for voltage?

Answer 14

Voltage (V) is measured in Volts (V) using a voltmeter.

Question 15

What is the formula for resistance?

Answer 15

Resistance (R) is measured in Ohms (Ω) and can be calculated from current (I) and voltage (V).

Question 16

Fill in the blank: Current, symbol __, measures the ________ of electrons flowing in a circuit.

Answer 16

I, amount

Question 17

Fill in the blank: Voltage, symbol V, measures the amount of __________ being carried by the electrons.

Answer 17

energy

Question 18

Fill in the blank: Resistance, symbol R, is what __________ the electron flow.

Answer 18

slows

Question 19

What does an ammeter measure?

Answer 19

An ammeter measures current in amps (A) and is placed in series with the circuit.

Question 20

What does a voltmeter measure?

Answer 20

A voltmeter measures voltage in volts (V) and is placed in parallel with the component.

Question 21

What is the purpose of a multimeter?

Answer 21

A multimeter is used to measure both current and voltage in circuits.

Question 22

What is Ohm’s law?

Answer 22

Ohm’s law describes the relationship between current, voltage, and resistance.

Question 23

What should you do before turning the circuit on when using a multimeter?

Answer 23

Ensure the multimeter is set up correctly and ask the teacher first

Question 24

What does Ohm’s law describe?

Answer 24

The relationship between current, voltage, and resistance

Question 25

What are the three variables in an Ohm's law investigation?

Answer 25

* Independent variable * Dependent variable * Control variable

Question 26

What equipment is needed to investigate Ohm's law?

Answer 26

* Power pack * Light bulb or resistor * Switch * 2 multimeters * 5 wires

Question 27

What is the first step in the Ohm's law experiment?

Answer 27

Build the circuit and get it checked before starting

Question 28

Fill in the blank: As the voltage increases, the current ______ if resistance remains constant.

Answer 28

increases

Question 29

What happens to the current if the resistance is increased while keeping the voltage constant?

Answer 29

The current decreases

Question 30

What is the formula given by Ohm's law?

Answer 30

V = IR

Question 31

If the current is 0.5 A and the resistance is 150 Ω, what is the voltage?

Answer 31

75 V

Question 32

What is the independent variable when investigating how changing resistance affects current?

Answer 32

Resistance

Question 33

In a series circuit, how does the current behave?

Answer 33

The current is the same at all points

Question 34

In a series circuit, how is voltage distributed among components?

Answer 34

The voltage is shared or divided between components

Question 35

What happens to the second bulb in a series circuit if the first bulb breaks?

Answer 35

The second bulb goes out

Question 36

In a parallel circuit, how does the current behave?

Answer 36

The current is divided among the branches

Question 37

What is the total current in a parallel circuit?

Answer 37

The total current is the sum of the currents in each branch

Question 38

True or False: The voltage in a parallel circuit is the same in each branch.

Answer 38

True

Question 39

What does the total resistance in a series circuit equal?

Answer 39

The sum of the individual resistances

Question 40

What happens to the total resistance when resistors are added in parallel?

Answer 40

The total resistance is less than the sum of the individual resistances

Question 41

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

Answer 41

1/R_tot = 1/R1 + 1/R2 + ...

Question 42

In the context of Ohm's law calculations, what is calculated when given voltage and resistance?

Answer 42

Current

Question 43

What is the conclusion about voltage when two identical bulbs are connected in series?

Answer 43

Each bulb receives an equal share of the voltage

Question 44

How do you calculate resistance using Ohm’s law?

Answer 44

R = V/I

Question 45

What is the result of a current of 2.5 A flowing through a heater with a p.d. of 240V?

Answer 45

Resistance of the heater is 96 Ω

Question 46

What should be done after building a series circuit with multiple bulbs?

Answer 46

Measure and record total voltage and current, then calculate resistance

Question 47

What is the formula for total resistance in a series circuit?

Answer 47

Rtot = R1 + R2 + R3 …..etc.

Question 48

If a circuit contains 2 resistors in series with values of 250 ohms and 450 ohms, what is the total resistance?

Answer 48

700 ohms

Question 49

In a series circuit with a total resistance of 500 ohms and 2 identical bulbs, what are the resistance values of the bulbs?

Answer 49

250 ohms each

Question 50

In a series circuit with a total resistance of 300 ohms and one resistor of 200 ohms, what is the resistance of the second resistor?

Answer 50

100 ohms

Question 51

What is the total resistance of a circuit containing 2 pairs of identical resistors with resistances of 200 ohms and 500 ohms?

Answer 51

700 ohms

Question 52

If a circuit has 4 resistors in series with values of 340, 120, 45, and 2500 ohms, what is the total resistance?

Answer 52

3005 ohms

Question 53

If a circuit has a total resistance of 1500 ohms with 5 identical resistors, what is the resistance of each resistor?

Answer 53

300 ohms

Question 54

In a circuit with 3 resistors totaling 500 ohms, if two resistors are 150 ohms and 45 ohms, what is the resistance of the third resistor?

Answer 54

305 ohms

Question 55

If a circuit contains 3 resistors with a total resistance of 1000 ohms, and R1 and R2 have twice the resistance of R3, express the resistances in terms of R3.

Answer 55

R1 = 2x, R2 = 2x, R3 = x

Question 56

What is the formula for the combined resistance of resistors in parallel?

Answer 56

1/R = 1/R1 + 1/R2 + 1/R3 + ...

Question 57

If a 25 ohm and a 100 ohm resistor are connected in parallel, what is the combined resistance?

Answer 57

20 ohms

Question 58

In a circuit with a 50 ohm, 150 ohm, and 10 ohm resistor connected in parallel, what is the total resistance?

Answer 58

6.93 ohms

Question 59

If 4 resistors each of 250 ohms are connected in parallel, what is the total resistance?

Answer 59

62.5 ohms

Question 60

If 3 identical resistors are connected in parallel giving a total resistance of 10 ohms, what is the resistance of each resistor?

Answer 60

30 ohms

Question 61

Define power in terms of electrical energy.

Answer 61

Power measures how quickly energy is converted.

Question 62

What is the formula for calculating power from current and voltage?

Answer 62

P = I x V

Question 63

Calculate the power of a light bulb with a voltage of 240 V and a current of 0.1 A.

Answer 63

24 W

Question 64

How much energy has a 1200 W microwave consumed if it runs for 600 s?

Answer 64

720,000 J or 720 kJ

Question 65

What is the relationship between power, energy, and time?

Answer 65

Power (in Watts, W) = Energy (in Joules, J) / time (in seconds, s)

Question 66

If a kettle has a power rating of 2.4 kW, how long would it take to boil 1 litre of water requiring 340 kJ of energy?

Answer 66

51 minutes

Question 67

If a microwave oven has a power rating of 1200 W, what current would it use when connected to a 240 V mains supply?

Answer 67

5 A

Question 68

Which of the two bulbs has the greatest resistance: a 240V bulb with 0.35 A or a 100 W bulb at 240 V?

Answer 68

The 100 W bulb has greater resistance