Electricity Flashcards
(32 cards)
Can electricity be in positive and negative charges?
Yes
What do positively charged objects lose?
Electrons
What do negatively charged objects gain?
Electrons
What does a conductor do?
Allows electric charge to flow through it.
What does an insulator do?
Does not allow electric charge to flow
What is current?
The rate of flow of electric positive charge
Explain how current adds up in a series circuit.
Current is the same at all points throughout the circuit.
Explain how current adds up in a parallel circuit.
The total current is the sum of the currents flowing through each branch.
What is voltage?
Measure of the difference in electrical potential energy.
What equals total supply voltage?
The sum of potential differences around a circuit
What is resistance?
The ratio of potential difference across a component to the current through that component.
Describe an experiment to determine resistance using an ammeter and voltmeter.
What does resistance equal?
Voltage/ Current
What is Ohm’s Law?
V = IR
Calculate the combined resistance of 2 or more series resistors
Describe the simple experiments to show the production and detection of static charge
Production of Static Charge by Friction, to produce static electricity by rubbing two different materials together. When you rub the comb or balloon with the wool cloth or fur, electrons are transferred from one material to the other. This transfer of electrons causes one object to become negatively charged (gains electrons) and the other to become positively charged (loses electrons). The static charge on the comb or balloon creates an electric field that induces a charge on the small pieces of paper, causing them to be attracted to the charged object.
Explain charge differences in static electricity.
Static electricity is all about the imbalance of electric charges on the surface of objects. This imbalance creates an electric field that can cause various effects. Static electricity occurs when electrons are transferred from one material to another.
Why does static electricity cause hair to stand on air?
When you comb your hair with a plastic comb, electrons are transferred from your hair to the comb. From this the hair becomes positively charged. From this each strand of hair has the same positive charge. Like charges repel each other so they try to move from each other and as they are rather light weight they ‘stand up’.
Why does static electricity make balloons pick up paper?
When the balloon becomes statically charged it gets a negative charge from picking up electrons. The balloon’s negative charge induces a positive charge on paper closest to the balloon. This happens because the balloon’s electric field causes the electrons in the paper to move slightly away, leaving the near side of the paper with a positive charge. So as opposite charges attracts the balloon picks up the piece of paper.
Design a circuit to distinguish between conductors and insulators.
battery - material- bulb - battery
What is resistance in circuits?
A measure of how much a material or component opposes the flow of electric current, measured in ohms (Ω). Resistance occurs because as electrons move through a conductor. This opposition to the flow of electrons is what we call resistance. Ohm’s Law means for a given resistance, the voltage across a component is directly proportional to the current flowing through it. It is a key factor in designing and analysing electrical circuits, affecting everything from current flow to voltage.
What is the difference between high and low resistance?
Higher resistance means less current will flow for a given voltage. Lower resistance= easier current flow.
What are the 3 roles of resistance in circuits?
Controlling Current: By adding resistors to a circuit, you can control the amount of current that flows through different parts of the circuit.
Power Dissipation: Resistance causes electrical energy to be converted into heat. This is why resistors can get warm when current flows through them. The power dissipated as heat in a resistor is given by:
P= I squared X R
or
P= V squared divided by R
Describe an experiment to determine resistance using an ammeter and a voltmeter.
By accurately measuring the voltage across the resistor and the current flowing through it, you can determine the resistance of the resistor using Ohm’s Law.
