Download ENERGY UNIT Answer Key

Energy Unit Study Guide
Name _________________________
1. What is energy? _The ability to do work._
2. What are the 7 types of energy? _Mechanical_ , __Thermal_, _Chemical_,
_Electrical_ , __Radiant_ , __Sound_, _Nuclear_
3. What type of energy can be divided into kinetic and potential energy? __ Mechanical__
4. What is kinetic energy? __Energy in the form of motion____
5. What is potential energy? __Energy due to an object’s position or location. Stored energy.__
6. Give three examples of electromagnetic energy. Visible light, ultraviolet light, microwaves AND the
Sun, light bulbs, and microwaves
7. A lightbulb gives produces what type(s) of energy? _Radiant (light) and Thermal (Heat)___
8. Which type of energy is stored in the nucleus of atoms? _Nuclear energy__
9. Foods contain __chemical__ energy, which is a form of _Potential_ energy
because it is stored inside the food. Muscles then convert _chemical_ energy into
_mechanical (kinetic)_ energy.
10. The _Law of Conservation of Energy_ states that energy cannot be created nor
destroyed. It can only be _transferred_ to other objects or _transformed_ into other
types of energy.
11. When a car uses a battery to start, what forms of energy is the chemical energy in the battery transformed
into? __electrical __
12. Is the energy from the car lost? Yes or No. Explain why or why not. The energy is not lost, it is just
transformed into another form of energy. The Law of Conservation of Energy states no energy
is created not lost.
13. What does energy efficient mean? _ an item loses a lower percentage of energy to unwanted
forms – an energy efficient dryer uses less power, but performs better with less loss of energy_
14. A solar cell changes energy from sunlight into what other type of energy? _ electrical_
15. When a rubber band is stretched it has what kind of energy?_elastic potential energy_
16. An apple hanging on a branch of a tree has what two types of energy? Chemical energy in the sugars
stored within it and mechanical potential energy due to its position
17. The metal handle of a spoon in a bowl of soup becomes warm due to heat transfer by the process of
_conduction_. How is the heat transferred? Heat flows directly from one substance to another
when objects touch
18. What is the definition of convection? Give one example. The transfer of heat by movement, such as
in liquids & gases – cold air is heavier and sinks while warm air is lighter and rises
19. Food restaurants keep food hot with infrared lamps. The heat is transferred to the food by a process
called _radiation_. Explain. _Electromagnetic waves carry heat and light – the sun can warm
your sking with heat, but also burn it with ultraviolet light_
20. Which is an example of an electrical conversion: (a) sunlight being reflected off the surface of a pond OR
(b) electrical energy being changed to mechanical energy in a blender? ________
21. What energy is necessary to create a magnetic field? _electrical_
22. A generator changes _mechanical_ energy to _electrical_ energy.
23. What is the energy conversion of an electric motor? The motor changes electrical energy into
mechanical energy
24. A coil of wire spinning around a magnet or a magnet spinning around a coil of wire can form a(n)
_magnetic field_.
25. What is the force of attraction or repulsion of magnetic materials? _magnetism__
26. What applies force without actually touching an object? _a magnet_
27. An _electromagnet_ is formed when a wire (in an electric current) is wrapped around an
iron core.
28. What happened to the magnetism of an electromagnet if the electric current stops flowing?
_the current stops completely_
29. Identify the source, resistor, and conductor in the diagram below.
Source _the battery__
Resistor _light bulb (the holder)__
Conductor __the wire___
30. How does energy flow in a series circuit? _in one direction__
31. How does energy flow in a parallel circuit? __in more than one path__
32. What kind of charge does an electron have? _negative__
33. Define and list three examples of a conductor. A conductor is anything that allows energy to pass
through. Examples are: metals such as aluminum, copper, iron, an steel conduct
electricity/metals such as aluminum, copper, iron, and steel as well as glass conduct thermal
energy
34. Define and list three examples of an insulator. Insulators stop or slow down energy. Electrical insulators
include glass, rubber, cotton, wood, plastic, & paper. Thermal insulators are plastic, rubber,
wood, & wool
35. As particles move faster in a substance, what happens to the temperature? The faster particles move,
the hotter the particles get, the slower they move, the cooler they are.
36. What insulates a sleeping bag best: aluminum foil, feathers, or air? _feathers__
Explain your answer. _Just as birds use feathers to insulate their bodies against heat and cold,
feathers stuffed between layers of a sleeping bag will form a barrier to cold.__
37. Where does heat move to? _Heat moves from warm to cold to heat other objects or
subtances_
38. By what method of heat transfer does the Sun heat the earth? _radiation__
Explain _electromagnetic waves travel from the Sun to Earth through space_
39. If you build a solar still to heat water, what color best attract heat from the Sun to heat the water quickly?
_dark colors/black_. Why? _dark colors absorb electromagnetic waves while light colors
reflect electromagnetic waves__
40. What is the definition of work? _the use of force that causes an object to move in the direction
of the force.__
41. When force is exerted on an object, work is done only if the object _moves_.
42. In this picture of a roller coaster, describe the mechanical energy at each point.
Point A: _Mostly Potential energy_
Point B: _Losing Potential Energy & gaining Kinetic Energy_____
Point C: _Mostly Kinetic Energy__
Point D: _Losing Kinetic Energy & Mostly Potential_
43. What energy is exerting force at the top of the hill?
_gravitational potential energy_
44. Where is the kinetic energy the greatest? _C_