Unit 3 Test: Electricity & Magnetism

Front

Resistance of a circuit with 10V and 5A using Ohm's law?

Back

2 ohms

Answer explanation

Using Ohm's law, R = V/I. Here, V = 10 volts and I = 5 amps. Thus, R = 10V / 5A = 2 ohms. Therefore, the correct answer is 2 ohms.

Front

Device that converts electric energy to sound energy.

Back

buzzer

Answer explanation

Jeff’s father needs a device that converts electric energy to sound energy. A buzzer fits this description as it produces sound when powered by electricity, unlike the other options which serve different functions.

Front

What does the bulb represent?

Back

Resistor

Answer explanation

The bulb represents a resistor because it limits the flow of electric current and converts electrical energy into light and heat, which is characteristic of resistive components.

Front

What is the energy source?

Back

Battery

Answer explanation

The energy source in this context is the battery, as it provides the electrical energy needed to power devices like bulbs. The switch and diode are components that control or direct the energy, but they do not generate it.

Front

What has alternating electric and magnetic fields that travel in the form of a wave?

Back

electromagnetic radiation

Answer explanation

Electromagnetic radiation consists of alternating electric and magnetic fields that propagate as waves. This includes visible light, radio waves, and other forms of radiation, making it the correct answer.

Front

What kind of device is an alternator in automobiles used to power things like the lights and the radio?

Back

generator

Answer explanation

An alternator is a type of generator that converts mechanical energy into electrical energy, supplying power to the vehicle's electrical systems like lights and radio.