Big energy issues and particles at work Flashcards
Which energy sources can meet variations in energy demand?
Gas-fired power stations and pumped storage stations can meet variations in demand.
What are the benefits and drawbacks of building non-renewable vs renewable sources of power?
Nuclear power stations are expensive to build, run and decommission. Carbon capture of fossil fuel emissions are expensive. Renewable resources are cheap to run but expensive to install. Renewable energy resources are unreliable. the amount of electricity they generate depends on the conditions.
Name the main flaw of hydroelectric power
An upland reservoir could run dry
Name the main flaw of wind and wave power
Wind and waves too weak on calm days to generate power
Name the main flaw of tidal power
Height of tide varies both on a monthly and yearly cycle
Name the main flaw of solar power
No solar energy at night, and variable during the day.
Name the ways in which non renewable and renewable energy sources can work together to meet the variable demand for electricity.
- Using nuclear and coal stations can provide the base load demand for electricity
- Using gas fired power stations to meet daily variations in demand and extra demand in winter
-Using renewable energy resources when demand is high and when the conditions for renewable energy generation are suitable (eg use turbines when wind speed is high) - Using renewable energy resources when demand is low to store energy in pumped storage schemes
Compare costs for non renewable power stations and renewable energy sources in terms of capital (buying/building/maintaining) and overall costs.
-Capital costs are lowest for gas fired power stations and greatest for wind power and nuclear power, including decommissioning costs.
-Overall costs including fuel costs are the lowest for hydroelectricity and greatest for offshore wind farms.
What happens when you rub an insulator against another one?
Electrons are transferred from one material to the other, the one that gains it has negative charge, the one that loses becomes positive.
How can two charged objects exert a non-contact force on each other due to their charge?
Because the first charged object create an electric field around itself, the second has a force exerted on it due to the field. As they move closer to each other, this effect grows stronger.
What is a line of force?
The path a small positive charge would follow due to an electric field.
When a charged object exerts a force on another, what happens if the field created is too strong?
Sparks occur as some electrons are pulled out of molecules in the air, hitting more air molecules and knocking more electrons out of them too. It creates a sudden flow of electrons between the two charged objects.
What happens to the line of force when an object is positively, versus negatively charged?
If an object is positively charged, the lines of force are pointing away from the object. If negatively charged, the lines of force point towards the object.
What is the rule of charges between objects?
Like charges repel. Unlike charges attract.
Explain why you may get an electric shock if you walk on a nylon carpet then touch a metal radiator
When you walk on a nylon carpet, friction between your feet and the carpet causes a buildup of static electricity on your body. When you touch a metal radiator, the excess charge rapidly discharges into the metal, giving you a small electric shock.
Explain why you sometimes get an electric shock when you get out of a car seat
When you get out of a car seat, friction between your clothes and the seat generates static electricity on your body. As you exit and touch a metal part of the car, the built-up charge discharges, causing a shock.
In a circuit, what does an indicator do?
An indicator like a light bulb is designed to emit light as a signal when current passes through it.
In a circuit, what does an ammeter do?
Is a component used to measure electric current
In a circuit, what does a fixed resistor do?
Limits the current in a circuit
In a circuit, what does a variable resistor do?
Allows the current to be varied
In a circuit, what does a fuse do?
It is designed to melt and break the connection in the circuit if the current exceeds a limit.
In a circuit, what does a voltmeter do?
Measures potential difference ( voltage)
In a circuit, what does a diode do?
Only allows current to flow in one direction
What is the equation for charge flow Q
Current I (A) x time taken T (S)
What is a battery made of?
Two or more cells connected together
What is the equation for potential difference across a component?
PD of component= energy transferred E / charge Q
What is the equation for resistance?
Resistance R = potential difference V / Current I
What does Ohm’s law state?
That the current through a resistor at a constant temperature is directly proportional to the potential difference across the resistor
What happens when you reverse the potential difference across a resistor?
It reverses the direction of current running through it.
What is potential difference?
Potential difference (also called voltage) is the difference in electric potential energy between two points in a circuit. It tells you how much energy is transferred per unit of charge as it moves between those points.
What is resistance?
Resistance is a measure of how much something opposes the flow of electric current through a circuit or component. It slows down the movement of electrons, converting electrical energy into heat. Resistance is measured in ohms (Ω), and higher resistance means less current flows for a given voltage.
Why is a wire called an ohmic conductor?
Because its resistance stays constant as the current changes, provided its temperature is constant.
