Show:
Properties of Matter
Circuits
Waves and EM Spectrum
Work, Power, Energy
Heat
100
What does it mean if something conducts electricity?
It lets electricity and heat pass through it.
100
What is the equation for Ohm's Law?
V=I xR also I=V/R also R=V/I
100
Name one device that uses infrared light.
Night vision goggles, photo film, heat lamps, tracks weather
100
Identify each variable in the equation W=Fd. (Must get each part correct to earn credit)
W=work F=force d=distance
100
A pot of water is allowed to heat up over a camp fire. The water starts to boil and evaporate. You grab the handle of the pot to pull it off the fire and it burns your hand. Identify an example of conduction in the example.
Conduction is a heat transfer through direct contact. In the example, heat is transferred to your hand from the pot through conduction when you pull it off the campfire.
200
What does it mean if something is a good insulator?
It does not let electricity pass through it.
200
Identify what each variable in the equation V=IR stands for.
V=voltage I=current R=resistance
200
How is wavelength related to frequency?
As wavelength increases, (waves get longer), the frequency decreases.
200
If a crane does 130,000 J of work as it lifts a car 25 m, what force did the crane lift with? W=Fd
5,200 N (F=W/d; F=130,000/25)
200
A pot of water is allowed to heat up over a camp fire. The water starts to boil and evaporate. You grab the handle of the pot to pull it off the fire and it burns your hand. Identify an example of convection in the example.
Convection is a transfer of heat through the movement of a liquid or gas based on density differences. In the example, convection was happening when the water heated up and evaporated up into the air, (rises because it is less dense).
300
What is a semiconductor?
Something that allows some electricity to pass through it.
300
Find the resistance of a flashlight that uses a 36 V power supply and draws a current of 0.60 A. R=V/I
60
300
How is the energy of a wave related to its frequency and its wavelength? (Must answer both parts to get credit)
As the energy increases, the frequency increase but the wavelength decreases.
300
John does 4,800 J of work as he rows across a lake in 40 seconds. What is John's power output? P=W/t
120 watts
300
How is radiation different from conduction and convection?
Radiation is a transfer of heat through electromagnetic, (EM), waves. Radiation can travel through outer space where there is no air. Conduction and convection cannot do that.
400
What group of elements make good semiconductors?
Metalloids.
400
Use the electric power equation, P=IxV to find the current that is produced in a TV that has a power rating of 480 W and is connected to a 120 V power source.
4 (I=P/V; I=480/120)
400
Which wave, ultraviolet or infrared, has the longer wavelength? Which has the greater frequency? (Must answer both correctly to earn credit)
Infrared has the longer wavelength. Ultraviolet has the greater frequency.
400
Explain the Law of Conservation of Energy in your own words.
Energy cannot be created and it cannot be destroyed. It is just transferred from one kind of energy to the next.
400
Compare the kinetic energies of a substance in its solid, liquid, and gas forms. Which has the highest, medium, and lowest amount of kinetic energy?
Kinetic energy is energy of motion. The particles in a solid barely move, so they have the lowest kinetic energy. Liquids move a little, so they have a medium amount of kinetic energy. Gases move the most, so they have the highest kinetic energy.
500
Why are computer chips made of semiconductors?
Semiconductors only let some electricity pass through, so they do not heat up too much.
500
What is potential difference in a circuit? What term is it also known as? (Must answer both correctly in order to get credit)
Potential difference is the imbalance in energy between the battery and the rest of the circuit that causes the electrons to be pushed out of the battery. It is also known as voltage.
500
Which color light, red or green, has the longer wavelength? Which has the higher frequency? (Must answer both parts correctly to earn credit)
Red light has the longer wavelength. Green light has the higher frequency. (This is because red light is closer to the infrared side of the EM spectrum and green light is closer to the ultraviolet side of the EM spectrum).
500
How does potential energy and kinetic energy change as a ball rolls down a hill?
The ball has all potential energy at the top of the hill, as it rolls down the hill, the potential energy transforms into kinetic energy. At the bottom, there is all kinetic energy.
500
What is the difference between heat and temperature? Which has more heat, a burning match or a 20 pound bag of ice? (Must answer both correctly to earn credit)
Temperature is a measure of the average kinetic energy of the particles of a substance, (how fast they move). Heat is the total energy transferred from objects changing temperature. The 20 pound bag of ice would have more heat, because heat is the TOTAL energy transferred, not just the average like temperature. The more particles an object has, the more heat it has.