science (static electrcity)

Question 1

Describe how objects can become charged

Answer 1

Objects can become charged when electrons transfer from one object to another. This can happen through friction when two materials rub against each other, causing electrons to transfer from one material to the other. The material losing the electrons becomes positively charged, while the material gaining electrons becomes negatively charged.

Question 2

Identify situations in which static electricity occurs

Answer 2

• when hair rubs against a brick wall
• when hair rubs against a ballon

Question 3

• Describe situations in which static electricity is useful and situations in which it is a nuisance

Answer 3

Useful :
- when air purifiers use static electricity to attract and remove particles in the air
- when laser printers use static electricity attract particles to the paper
Nuisance :
- getting a electric shock from metal
- clothes sticking together

Question 4

• Describe what happens when charges are brought close to each other

Answer 4

When like particles come close together, they repel ( for example when a positive charge comes close with another positive charge they repel) and when two opposite charge come close together they attract

Question 5

Investigate everyday situations where the effects of electrostatic forces can be observed eg lightning strikes during a severe storm

Answer 5

For example, when a comb runs through your hair, the electrons transfer between the comb and your hair.
Another example is getting a electric shock when you touch metal

Question 6

Define the terms ‘current’, ‘voltage’ and ‘resistance’

Answer 6

Current :refers to the flow of electric charge through a conductor. Electric current is the rate of flow of electric charge past a point in a circuit.
Voltage is the measure if the electrical energy that is carried by the charges in a circuit
Resistance is a measure of how much of a load ( e.g. globe, motor, resistor) restricts and reduces the flow of current

Question 7

Identify the symbols for current, voltage and resistance and their units of measurement

Answer 7

CURRENT : I and amperes
VOLTAGE: V and volts
RESISTANCE: R and Ohm

Question 8

Describe voltage, resistance and current using analogies

Answer 8

For example
Water Hose Analogy :
- the current is the flow of the water in the pipe
- the voltage is the measure of the electrical pressure carried by the charges in a circuit like the pressure of the water in the pipe
- the resistance is how much the water flow is reduced and restricted when the water goes through the narrower parts of the pipe

Question 9

What is potential difference?

Answer 9

Potential difference, also known as voltage, refers to the difference in electric potential between two points. ( THE UNIT IS V - VOLTS)

Question 10

What happens to the resistance according to the look of the wires?

Answer 10

The longer the wire the higher the resistance as Longer wires have more atoms, making it more likely for electrons to collide, which increases resistance. The thicker the wire the lower the resistance because the less likely for electrons to collide.

Question 11

Outline how current and voltage can be measured in circuits

Answer 11

Current is measured using an ammeter connected in series with the circuit, providing a direct reading in amperes (A). Voltage is measured using a voltmeter connected in parallel

Question 12

Describe the relationship between voltage, resistance and current in a simple circuit

Answer 12

• increasing the voltage will cause the current to increase, while increasing the resistance will cause the current to decrease ,
• If the resistance (R) is increased and the voltage (V) remains constant, the current (I) will decrease.
• Conversely, if the current (I) is to be increased while keeping the resistance (R) constant, the voltage (V) must be increased.
• This is proven by the ohms law which states V : I X R

Question 13

• Compare the characteristics and applications of series and parallel circuits

Answer 13

• In a series circuit, the components are connected one after another in a row. As a result,the same current flows through each components, the voltage, however ,is shared between each of the components and if you connect more then 1 lightbulb they will glow dimmer but in parrell there will be no effect on the brightness beacuse the voltage stays teh same
• In a parallel circuit, the components are connected in separate brunches As a results ,the current is divided between each of the components, but each branch of a parallel circuit uses the full voltage provided by the power supply

Question 14

Solve simple problems using Ohm’s Law, and define it.

Answer 14

OHMS LAW STATES THAT V = I X R ( VOLTAGE = RESISTANCE TIMES CURRENT)
AND THEN FOR R = V DIVIDED BY I
THEN FOR I = V/R

Question 15

Compare AC and DC electricity

Answer 15

AC
- THE MAGNITUTE OF THE CURRENT CHANGES AS WELL AS THE DIRECTION CONTUNISLY
- AC IS PRODUCED IN POWER STATIONS
- AC CAN BE TRANSMITTED TO LONG DISTANCES

DC
- THE DIRECTION OF CURRENT REMAINS UNCHANGED
- AC IS PRODUCED BY CELLS AND BATTERIES
- DC CANNOT BE EASILY TRANSMITTED TO LONG DISTANCES

Question 16

Apply the law of conservation of energy to energy transfers and transformations in common household electrical appliances

Answer 16

• Energy cannot be created or destroyed, only transformed.
  Examples: Toaster (electrical to heat), blender (electrical to mechanical)

Question 17

• Describe the features of electrical circuits in the home, including safety features

Answer 17

THE IS A RANGE OF ELECTRICSL SAFETY CIRCUTS THAT SHUT OFF ELECTRICITY FLOE IN THE EVENT OF AN OVERLOAD OR GROUND FAULT IN THE CIRCUT.thse include circut breakers (safety devices between the sockets in the home and the mains supply from the street which automatically shuts down if theres a short circut).
a fuse is a device that contains a thin mire that melts if the current is to high breaking the circuit and protectng the fuse cable from overheating.

Question 18

Describe how electrical energy use is monitored and charged

Answer 18

Energy monitors: These devices are connected to the electricity meter and record the amount of energy used.
Smart energy monitors: These devices monitor how much energy your home uses and provide insights.
Energy use apps: Install an app connected to a monitoring meter to track energy consumption.
Conduct an energy audit: Assess your home’s energy usage to identify areas for improvement.

Question 19

• Describe how generators create electricity and relate this to the commercial production of electricity in power stations

Answer 19

Generators convert mechanical energy to electricity in power stations.
- Generators use electromagnetic induction to convert mechanical energy (from turbines) to electrical energy.
Power stations produce electricity on a large scale for distribution.

Question 20

Identify examples of renewable and non-renewable energy sources

Answer 20

Renewable: Solar, wind, hydroelectric, geothermal.
Non-Renewable: Coal, oil, natural gas, nuclear.
Renewable Source: A renewable source of energy is one that can be naturally replenished over a relatively short period of time, such as solar, wind, and hydroelectric power.

Non-Renewable Source: A non-renewable source of energy is one that exists in limited quantities and cannot be replenished on a human timescale, such as fossil fuels (coal, oil, natural gas) and nuclear energy.

Question 21

what is the term efficiency and its formula?

Answer 21

EFFCIENCY = useful output energy (J) / total input energy (j)

Question 22

what are insulators and conductors in circuts?

Answer 22

Conductors are materials that allow electrons to flow freely, such as copper. they have a lower resistance then insulators. Insulators, on the other hand, resist the flow of electrons, such as glass and plastic

Question 23

what do the components do in a circut?

Answer 23

Resistors: A resistor is a passive two-terminal component that limits the flow of electric current in a circuit.
Power Source (Cell or Battery): The power source provides energy to the circuit. It can be a battery or a generator. When connected, it supplies voltage to drive the current flow.
Conducting Wires: These wires act as conductors, allowing electric current to flow. Usually made of copper, they connect various components in the circuit.
Switch or Key: The switch controls the circuit. When closed, it completes the circuit, allowing current to flow. When open, it interrupts the flow.
Load (Bulb or Electric Device): The load consumes electrical energy. Examples include light bulbs, motors, or any other device that uses electricity.

Question 24

what are transformers? and transfers?

Answer 24

Energy transformation refers to the change of energy from one form to another.
Energy transfer refers to the movement of energy from one location to another.