Physics Chapter 18

Six resistors are wired in a parallel circuit. What is the voltage across each resistor in the circuit if the first resistor is connected to a 24V battery?

24V

If the terminal voltage across a battery is 4.5V, what is the potential difference across the machine?

4.5V

Which of the following devices is always connected in series with a household circuit?

A fuse

What distinguishes a parallel circuit from a series circuit?

A parallel circuit always has more than one current path.

Schematic diagram

A representation of a circuit that uses lines to represent wires and various symbols to represent components

What is the difference between a single cell battery and a multiple cell battery?

A single cell will have one series of lines with differing lengths while a multiple cell will have multiple

Name two common emf sources

Batteries and generators

Assuming that you want to create a circuit that has current in it, why should there be no openings in the circuit?

Because open circuits do not allow a complete path for charge to flow, there will be no current

Do charges move form a source of potential difference into a load or through both the source and the load?

Charges move through both the emf source and the load

Parallel circuits do not require all elements to do what?

Conduct (There are multiple routes within the circuit for energy to travel)

Series circuits require all elements to do what?

Conduct current (if one load burns out, the rest will too).

Wires that connect elements are called

Conductors

You have three 100 ohm resistors available. How would you connect theses resistors to produce a 150 ohm Req?

Connect one resistors in series with two resistors in parallel

A circuit breaker is designed to limit the amount of _____________ in a circuit

Current

Series

Describes two or more components of a circuit that provide a single path for current

Parallel

Describes two or more components of a circuit that provide separate paths for current because they are connected across common junctions

A load in a circuit does what?

Disspates energy

Why must the equivalent resistance for a parallel arrangement of resistors must always be less than a single resistor?

Due to the reciprocal relationship (inverse) of parallel circuits

Suppose a 9V battery is connected across a lightbulb. In what form is the electrical energy supplied by the battery dissipated by the lightbulb?

Energy dissipates in the form of heat and light in the bulb and in the form of heat in the wires

Briefly describe how to find the equivalent resistance of complex circuit

If there are resistors in parallel, add the inverse of their values (inverse them again) to condense it into series format where you can add the values together.

In any complex circuit, the current through any resistor in the circuit is always

Less than the total current through the circuit

What do fuses do?

Protect electrical devices by opening a circuit if the current in the circuit is too high.

Why are schematic diagrams useful?

Schematic diagrams allow visualization of circuit elements, which can be especially useful in the case of complicated circuits

Several resistors are wired in a circuit so that there is a single path for the flow of electric current. What type of circuit is this?

Series

A circuit it constructed as follows: four resistors in parallel connected in series with three resistors in parallel, connected in series with two resistors in parallel. All resistors have the same value. How does the Req compare to the resistance of a single resistor?

The Req is greater than a single resistor

What does emf stand for?

The energy per unit charge supplied by a source of electric current

Four resistors having equal values are wired as a parallel circuit. How does the equivalent resistance of the circuit compare to the resistance of a single resistor?

The equivalent resistance if one-fourth the resistance value of a single resistor

Five resistors are wired in a series circuit. How does the equivalent resistance of the circuit compare to the resistance of the individual resistors?

The equivalent resistance is greater than any single resistance

A parallel circuit is composed of any number of resistors all of equal value. What simple process can you use to determine the equivalent resistance of such a circuit?

The equivalent resistance is the inverse of all resistances added together, and then inversed again.

Resistors are shown has having multiple, rapid bends illustrating what in a schematic diagram?

The increased resistance to the movement of the charges

The part of a circuit that converts electrical energy to other forms of energy is...

The load

Because household devices are connected in parallel in a circuit _____________ as new devices are connected

The potential difference remains the same

Several resistors are wired in a series. What is consistent about the circuit?

The total circuit current is the same as the current through any of the resistors?

Why is it dangerous to use an electrical appliance when you are near water?

When someone is near water or wet themselves, their conductivity is increased. If an electrical shock were to pass through them on its way to being grounded, serious injury or death could occur.

electric circuit

a set of electrical components connected such that they provide on or more complete paths for the movement of charges

Because wires offer negligible resistance, they are represented by ______________ in schematic diagrams

a straight line

You want to determine the current in a complex circuit. Which piece of info is least helpful in making your determination? a. the equivalent resistance of the circuit b. the number of devices in the circuit c. the current in each element in the circuit d. the voltage across each element in the circuit

b. the number of devices in the circuit

Two resistors and a battery are wired in a series circuit. One resistor has twice the resistance of the other resistor. What is true about the voltage across the two resistors? a. each resistors has half of the voltage b. a third of the voltage is going through the higher resistor c. a third of the voltage is going through the lower resistor d. two thirds of the voltage is going through the higher resistor

c. a third of the voltage is going through the lower resistor

What is another name for a schematic diagram?

circuit diagram

The source of potential difference and electrical energy is the....

circuit's emf

A closed-loop path for electrons to follow is called a

closed circuit

A short circuit is... a. potentially hazardous b. a circuit in which electrons cannot flow c. a circuit without a load and little resistance d. both a and c

d. both a and c

For conventional current, terminal voltage is ________ than the emf

less

The terminal voltage is always ________ than the emf of the battery

less than

The current through one resistor in a parallel resistor circuit is always

less than the total current in the circuit

If there is no charge flow and no current, it is called an

open circuit

The longer line in a schematic symbol for battery represents the

positive end of the battery

A lightbulb in a series can also act as a.....

resistor

Potential difference across a load equals the...

terminal voltage

Which is greater; emf of a battery or terminal voltage?

the emf of the battery