Topic 4 Electricity Test - Physics

Question 1

The Law of Conservation of Energy

Answer 1

Energy can neither be created nor destroyed;
Rather, it transforms from one form to another. All objects have energy, but differ in the amount and form of energy they carry

Question 2

Potential Energy

Answer 2

The energy of an object due to its position, this energy can be stored and used in the future

Question 3

Kinetic Energy

Answer 3

The energy created due to the motion of an object

Question 4

Thermoelectric Effect, who and when was it discoverd

Answer 4

When a temperature difference between 2 metals creates a voltage, which results in electon movement that creates elecricty. Also referred to as the Seebeck Effect, ot was discovered in 1821 by Thomas Seebeck.

Question 5

Thermocouple - Heat to Electricity

Answer 5

A loop of 2 different metals that conduct electricity at different rates. This produces a small potential difference and is used to measure temperature.

Question 6

Thermopile

Answer 6

Several thermocouples work together in a series to generate a larger voltage, which helps when measuring small temperature changes.

Question 7

How do thermocouples use voltage to measure temperature?

Answer 7

Heat makes electrons move faster, and the metals on a thermocouple react differently to heat, so one metal will have more electrons than the other. This difference in heat and electrons is what creates the potential difference/voltage. The higher the temperature, the higher the voltage.

Question 8

Thermo-Electric Generator

Answer 8

Turns heat into electricity by using the thermoelectric effect, where one side of the thermopile is kept cold, and one side is kept hot, which creates a small steady current.

Question 9

Piezoelectric Effect and who discovered it?

Answer 9

When pressure is applied to certain crystals, they generate a small voltage. This happens because the crystal’s atomic structure rearranges under pressure, causing an imbalance of electric charges. This effect also works in reverse: when a voltage is applied to the crystal, it vibrates and can cause attached objects to move. The piezoelectric effect was discovered by Jacques and Pierre Curie in 1880. Ex. BBQ lighter

Question 10

Photovoltaic Effect and who discovered it

Answer 10

Is when light is converted into electrical energy by causing electrons to move in a semiconductor. Discovered by Edmund Becquerel in 1839. Ex. Solar Panel

-Light hits a semiconductor
-The light gives energy to electrons
-The electrons break free and produce an electrical current.

Question 11

Photovoltaic Cells (Solar Cells)

Answer 11

Also called solar cells, uses the photovoltaic effect to convert light into energy by using a semiconductor, usually silicon, to capture light energy and transfer it to electrons to allow them to break free.

Question 12

What are LED’s?

Answer 12

Light-emitting diodes have a semiconductor that requires only a fraction of the current that a normal incandescent bulb uses.

Question 13

Fluorescent Lighting

Answer 13

Uses a currebnt that current that causes mercury vapour to produce and ultraviolet light.