Chapter 5

Magnetic fields can be created by the motion of electrical charges.

True

Muscle contractions are initiated by electrical signals.

True

Series circuits are likely to cause more trouble than parallel circuits to people looking for a burned out light in holiday decorations.

True

Which is not true of Maxwell's equations? a. Like charges attract, unlike charges repel. b. Coulomb's law c. There are no magnetic monopoles in nature. d. Magnetic phenomena can be produced by electrical effects. e. Electrical phenomena can be produced by magnetic effects.

a. Like charges attract, unlike charges repel.

A coil of wire is an optional component in every electrical generator.

False

An electrical device can be made more powerful by increasing the current flowing in the wire or decreasing the voltage.

False

Galvani invented the electromagnet.

False

Most atoms are electrically neutral because the number of protons equals the number of neutrons.

False

Ohm's Law shows a direct relationship between amps and volts.

False

The properties of the electrical force arise from one type of charge called electromagnetism.

False

An electric force in a static charge does not move once it has been placed.

True

Before lightning strikes, a victim's hair will have a positive charge.

True

Lightning rods on tops of buildings protect the structure by attracting the electric charges.

True

Signals are sent by the optic nerve to the brain by moving positively charged ions across membranes.

True

Some animals have magnets in their bodies to navigate up and down.

True

Static electricity is more powerful than gravity.

True

When electrical charges accelerate, electromagnetic waves are created.

True

In what way does Newton's law of universal gravitation differ from Coulomb's law? a. Electrical forces can be either attractive or repulsive, while gravity is only attractive. b.Only Newton's law of gravity requires a universal constant. c. Only Coulomb's law addresses distance in describing the effect of one object one another. d. All of the above represent differences. e. Newton's and Coulomb's laws are identical.

a. Electrical forces can be either attractive or repulsive, while gravity is only attractive.

Mary Shelley's Frankenstein was based on some experiments and demonstrations in electricity from a. Galvani's research. b. Voltaire's research. c. the writings of Allessandro Volta. d. Benjamin Franklin's research. e. William Gilbert's compass.

a. Galvani's research.

Electric fields and electric currents can be produced by a. changing magnetic fields. b. radiation. c. magnetic monopoles. d. electric eels and sharks. e. static electrical charges.

a. changing magnetic fields.

Voltage is to resistance as a. volt is to ohm. b. volt is to amp. c. volt is to watt. d. volt is to flow rate. e. volt is to power.

a. volt is to ohm.

How much electrical current will flow through a 250-watt stereo system to play a compact disk in the United States? a. 1.14 amps b. 2.17 amps c. 0.46 amps d. 28,750 amps e. You need more data to calculate the current.

b. 2.17 amps

Static cling is an example of a. the fact that there are no magnetic monopoles. b. Coulomb's Law. c. changing magnetic fields. d. alternating current. e. electromagnetism.

b. Coulomb's Law.

Every electrical circuit contains a. an electromagnet. b. a path through which the current can flow. c. a switch. d. a circuit breaker. e. low-resistance wires.

b. a path through which the current can flow.

How is the force of two charged particles related to their charges? a. proportional to the product of their charges divided by the cube of the distance between them b. proportional to the product of their charges divided by the square of the distance between them c. proportional to the ratio of their charges divided by the distance between them d. proportional to the ratio of their charges multiplied by the square of the distance between them e. No relation exists between charged particles and force.

b. proportional to the product of their charges divided by the square of the distance between them

Coulomb's law states that force is dependent on all EXCEPT a. the Coulomb constant. b. the difference in size between the two objects. c. the charge of the smaller object. d. the distance between the two objects. e.the charge of the larger object.

b. the difference in size between the two objects.

Which scientist was most influential in Coulomb's work? a. Benjamin Franklin b. James Clerk Maxwell c. Sir Isaac Newton d. Thomas Edison e. Michael Faraday

c. Sir Isaac Newton

The functioning of an electric motor depends on the fact that a. like charges attract, unlike charges repel. b. like magnetic poles attract, unlike magnetic poles repel. c. an electrical current produces a magnetic field. d. permanent magnets are always stronger than electromagnets. e. all motors must have several electromagnets.

c. an electrical current produces a magnetic field.

Which of the following items would use only low resistance wires? a. a toaster b. a space heater c. an electrical transmission line d. a light bulb e. a hair dryer

c. an electrical transmission line

A force field surrounding a charged object is a a. gravitational field. b. gravitational force. c. electrical field. d. electrical force. e. magnetic field.

c. electrical field.

The newest version of hybrid cars a. use magnetic monopoles. b. incorporate nuclear and electric motors. c. get above 50 miles per gallon on the highway. d. have lead-acid batteries. e. has altered car manufacturers' attitudes.

c. get above 50 miles per gallon on the highway.

Which of the following can produce magnetic fields? a. gravitational force b. static electrical force c. moving electrical charges d. increasing entropy e. all of the above

c. moving electrical charges

Hans Christian Oersted discovered the relationship between the forces of magnetism and electricity by a. many long years of tedious research. b. reading the writings of Galvani. c. paying attention during a physics lecture. d. interpreting his dreams. e. replicating the experiments of Volta.

c. paying attention during a physics lecture.

When you cut a magnet in half you get a. two north poles. b. two south poles. c. two north poles and two south poles. d. one magnetic monopole. e. one south pole and one north pole.

c. two north poles and two south poles.

William Gilbert discovered many important properties of magnets. Which of the following was not among Gilbert's findings? a. Every magnet has at least two poles. b. If magnetic poles are alike they repel each other. c. Steel rods can be magnetized by stroking them with a lodestone. d. Electric currents can be produced by changing magnetic fields. e. Iron's magnetism can be destroyed by heating.

d. Electric currents can be produced by changing magnetic fields.

In a famous experiment in the late 1700s, Charles Coulomb a. repeated Benjamin Franklin's kite and lightning demonstration. b. measured electricity with a galvanometer. c. proved Newton's three laws of motion. d. measured the force of the electric charge in objects. e. showed that muscle contractions are both electric and chemical.

d. measured the force of the electric charge in objects.

The load in an electric blow dryer is a. where the dryer plugs into the electrical outlet. b. where the electrical cord is attached to the dryer. c. in the on/off switch. d.in the heating element and fan. e. where the heated air is exhausted.

d.in the heating element and fan.

It is possible to make an electric current flow in a loop of wire by a. inserting a battery into the loop. b. static electrical charges. c. moving a magnet near the loop. d. spinning the loop in a magnetic field. e. a & c & d

e. a & c & d

In which of the objects below would you find an electromagnet? a. wall switch, buzzer, motors b. thermostats, electric drill, electric fan c. hair dryer, electric razor, power drill d. heater, food processor, CD player e. all of the above

e. all of the above

What are some ways the Earth's magnetic field is used for navigation? a. Sailors use compasses to direct their course. b. Some bacteria navigate down within pond ooze. c. Migratory birds are directed by the magnetic field. d. Australian silvereye can see the magnetic fields. e. all of the above

e. all of the above

What important practical device followed directly from Michael Faraday's work? a. the battery b.the thermostat c. the electromagnet d. the internal combustion engine e. the electric generator

e. the electric generator

In equation form, Ohm's Law states a. electrical pressure = flow charge/flow resistance b. current = voltage (volts) + flow charge (coulombs) c. power (watts) = current (amps) X voltage (volts) d. voltage (volts) = pressure (ohms) X resistance (ohms) e. voltage (volts) = current (amps) X resistance (ohms)

e. voltage (volts) = current (amps) X resistance (ohms)