Energy Unit Review

Two lamps, one with a thick filament and one with a thin filament, are connected in parallel to a battery. What explains why the lamp with the thicker filament burns more brightly?

• Thin filaments offer less resistance and are better at conducting electrons through a circuit.

• The lamp with the thin filament is closer to the battery, which causes the voltage to be higher.

• Thick filaments offer less resistance and allow more current to flow through the circuit.

• The higher voltage is due to faulty wiring, as the lamps would normally have the same brightness.

A student listens to the radio while doing homework. Which form of energy conversion occurs in the radio?

• electrical to chemical energy

• electrical to heat energy

• electrical to mechanical energy

• electrical to sound energy

Solar cells can be used to light a street lamp. Which option describes the energy transformation in this process?

• solar energy to chemical energy to electrical energy to light energy

• solar energy to electrical energy to chemical energy to light energy

• solar energy to chemical energy to mechanical energy to light energy

• solar energy to mechanical energy to chemical energy to light energy

In some states, the law mandates that a new house has to be built with insulation in the walls. Why would this be important to have?

• Cold outside air is prevented from getting inside the house.

• Heat from the outside air is absorbed.

• On cold days, it slows down the loss of heat.

• Heat is generated to keep the house warm.

Which cooking utensil would be the best conductor of heat energy when placed in boiling water?

• metal whisk

• plastic fork

• rubber spatula

• wooden spoon

Which action would require no work to be done on an object?

• pushing an object across the floor of a room

• lifting an object from the floor of a room

• holding an object still above the floor of a room

• dropping an object from a height above the floor of a room

Samantha tries to push a box of books across a storage closet. The box does not move, but Samantha feels tired. What can be concluded about the work performed on the box?

• Work was done on the box because Samantha was tired after using energy to push it.

• Work was done on the box because Samantha was tired after using force to push it.

• No work was done on the box because Samantha did not have enough energy to move it.

• No work was done on the box because Samantha did not have enough force to move it.

An airplane climbs from sea level to an altitude of 5,000 feet. What part of the plane performed the work?

• A strong tailwind pushed the plane higher.

• The plane's engine burned fuel and transferred energy to turn the propeller.

• The plane's wings created lift which elevated the craft.

• The pilot changed the rudder setting to allow the plane to rise.

The student wraps a metal sheet around a copper wire. She then hammers the metal several times. The temperature of the sheet rises, and it becomes even more flat. What type of energy transformation does the example involve?

• kinetic energy into heat energy

• kinetic energy into chemical energy

• potential energy into heat energy

• potential energy into chemical energy

A student turns on the classroom's ceiling fan and observes that the fan blades begin to move quickly. When the switch is turned off, the student observes that the blades begin to slow and eventually stop. Which statement best describes the student's observations of the movement of the ceiling fan's blades?

• Electrical energy is converted to mechanical energy to propel the fan blades, and stored elastic energy slows the fan blades until they stop.

• Electrical energy is converted to mechanical energy to propel the fan blades, and friction slows the fan blades until they stop.

• Electrical energy is converted to elastic energy to propel the fan blades, and friction slows the fan blades until they stop.

• Electrical energy is converted to elastic energy to propel the fan blades, and stored mechanical energy slows the fan blades until they stop.