Chapter 18 - Electrical Quantities - Part 1

The movement of electrons is called

• Voltage
• Current
• Resistance
• Power

The electrical force that pushes the electrons out of its orbit

• Current
• Voltage
• Resistance
• Power

Voltage is measured in

• Watts
• Amperes
• Ohms
• Volts

Current is measured in 

• Watts
• Ohms
• Amperes
• Volts

Resistance is measured in

• Watts
• Ohms
• Amperes
• Volts

This is the the work done by (a unit) charge passing through an electrical component; another name for the voltage between two points:

• ohm

• Direct Current (DC)

• electromotive force (emf)

• potential difference

• Alternating Current (AC)

Answer explanation

Voltage, also known as electric pressure, electric tension, or (electric) potential difference, is the difference in electric potential between two points. In a static electric field, it corresponds to the work needed per unit of charge to move a test charge between the two points. In the International System of Units (SI), the derived unit for voltage is named volt.

The voltage between points can be caused by the build-up of electric charge (e.g., a capacitor), and from an electromotive force (e.g., electromagnetic induction in generator, inductors, and transformers).On a macroscopic scale, a potential difference can be caused by electrochemical processes (e.g., cells and batteries), the pressure-induced piezoelectric effect, and the thermoelectric effect.

A voltmeter can be used to measure the voltage between two points in a system. Often a common reference potential such as the ground of the system is used as one of the points. A voltage can represent either a source of energy or the loss, dissipation, or storage of energy.

This is electric current that reverses its direction of flow in a regular pattern:

• ohm

• Direct Current (DC)

• electromotive force (emf)

• potential difference

• Alternating Current (AC)

Answer explanation

Alternating current (AC) is an electric current which periodically reverses direction and changes its magnitude continuously with time, in contrast to direct current (DC), which flows only in one direction. Alternating current is the form in which electric power is delivered to businesses and residences, and it is the form of electrical energy that consumers typically use when they plug kitchen appliances, televisions, fans and electric lamps into a wall socket. A common source of DC power is a battery cell in a flashlight. The abbreviations AC and DC are often used to mean simply alternating and direct, respectively, as when they modify current or voltage.

The usual waveform of alternating current in most electric power circuits is a sine wave, whose positive half-period corresponds with positive direction of the current and vice versa (the full period is called a cycle). In certain applications, like guitar amplifiers, different waveforms are used, such as triangular waves or square waves. Audio and radio signals carried on electrical wires are also examples of alternating current. These types of alternating current carry information such as sound (audio) or images (video) sometimes carried by modulation of an AC carrier signal. These currents typically alternate at higher frequencies than those used in power transmission.

The tendency for materials to oppose the flow of electricity is known as __________ and is measured using ___________.

• resistance, Ohms

• current, AMPS

• voltage, Volts

The rate of flow of electrons through a wire is known as __________ and is measured using __________.

• resistance, Ohms

• voltage, Volts

• current, AMPS

30 C of charge flowed through a wire in 10 s.

What is the current in the wire?

(a)