Chapter 6

1.

1 point

The aspect of electricity that would make it most dangerous is high

current

frequency

voltage

power

2.

1 point

The original superconductors were cooled with

liquid He

frecon refrigerators

liquid Nitrogen

hydrogen gas

3.

1 point

magnetism comes from

moving quanta of light

moving electric charge

magnetic monopoles

quantization of charge

4.

1 point

Static electricity occurs when two surfaces rub against each other and

electrons flow from one to another

neutrons flow from one to another

positrons flow from one to another

protons flow from one to another

5.

1 point

The current through a flashlight bulb is

about 110 amp

is about 1 amp

about 15 amp

about 1.6 x 10^-19 amp

6.

1 point

Edison wanted

a power plant on every city block

to abolish the electric chair

high voltage DC

alternating current

7.

1 point

A certain kind of generator uses its own electricity to strengthen its magnetic field. Such a generator is called a

superconductor

dynamo

samarium

transformer

8.

1 point

When an object loses some electrons, it

low resistance

glows

has positive charge

negative charge

9.

1 point

Topsy was executed with AC

because it was the only way to get high current

AC delivers more power than DC

to show the dangers of high voltage

because DC would not have worked

10.

1 point

The earths magnetic flips are used for

proving that the earth has a solid iron core

generating useful power

geologic dating

11.

1 point

the north geographic poles of the eath

is a south magnetic pole

has always had the same polarity

exactly at the magnetic pole

none of the above

12.

1 point

what discovery now allows for headphones to be small and light

maraging steel

rare earth magnets such as samarium colbalt

dynamos

transformers

13.

1 point

Which of the following use or consist of permanent magnets

losestones

transformers

compasses

earphones

all of the above

14.

1 point

magnetic monopoles

produced by cosmic rays

found in the earth core

have never been found

found at the ends of magnets

15.

1 point

Better motors and earphones have recently been made possible by

higher voltage batteries

stronger magnets

using light rather than electricity

wires and less resistance

16.

1 point

In a permanent magnet, the magnetism comes from

motion of protions

a spin of electrons

the electron avalnce

high voltage inside the atom

17.

1 point

A Telsa coil is a kind of

sensor for the curie point

transformer

radio transmitter

dynamo

18.

1 point

Submarines can be detected by their

electric charge

magnetism

backscattered xrays

MRI signals

19.

1 point

At the Curie temperature

magnetism disappears

molecular movement stops

fusion takes place in the sun

fission takes place in a bomb

20.

1 point

Europe uses higher voltage in homes because it

is less dangerous

works better for DC (used in Europe instead of AC)

creates less heat in home wiring

carries greater power

21.

1 point

A stereo speaker produces sounds by the force

of an electric field on a magnetic charge

of an electric field on an electric charge

of a magnetic field on electric current

of a magnetic field on an electric charge

22.

1 point

An example of a transformer is

rail gun

dynamo

Van de Graaff generator

Telsa coil

23.

1 point

We use AC instead of DC becuase

AC is cheaper than DC

AC can use transformers

DC can use transformers

110V AC is less dangerous than 110V DC

24.

1 point

The light from an ordinary light bulb comes from the fact that

the wire is heated by electricity

the wire contains phosphor

the high voltage causes small sparks

electricity is a wave

25.

1 point

Room temp superconductors

are used for strong magnets

have no practical applications

used in advance computers

used to carry electric power

26.

1 point

To reduce losses from Resistance, electric power lines uses

very high power

very high voltage

very low voltage

very high current

27.

1 point

theoretically, the earth should not have a permanent magnet in its core

there is not enough iron

interior is too hot

the earth spins

magnets do not occur naturally

28.

1 point

electricity will heat a wire if it has

DC rather than AC

high current

high frequency

high voltage

29.

1 point

High temperature superconductors operate at approx

-123C (liquid nitrogen tempt)

2000C

room temp

30.

1 point

A volt is a measure of

energy per electron

force on electron

density of electron

number of electrons per sec

31.

1 point

rail gun push the projectile using

magnetic fields

protons

high energy explosives

electric fields

32.

1 point

Telsa wanted to use a transformer to distribute electricity because

it decreased the current going through the long wires to reduce loss of electricity

allowed there to be a power plant in every neighbourhood

given strong support by Eddison

it made high voltage less dangerous

33.

1 point

The earth flips its magnetism, on average, approximately

once every billion years

twice every million years

never

once every 11 years

34.

1 point

A fuse is used in a house to prevent

large power surges

too much energy usage

illegal use of electricty

house wires from overheating

35.

1 point

Lights and TVs in Europe tend to flicker because Europe uses

220V - the U.S. uses 110V

110V- the U.S. uses 220V

60Hz-the U.S. uses 50Hz

50 Hz- the U.S. uses 60Hz

36.

1 point

You can demagnetize a natural magnet

by heating it above the Curie point

placing it in a very strong electric field

placing it on a tv or computer screen

none of the above

37.

1 point

Compasses point north because

there are magnetic monopoles near the North poles

the earth has an electric charge

there are electric currents in the iron core of the earth

the north star attracts them

38.

1 point

To get a spark, you normally need

low resistance

high voltage

alternating current

high current

39.

1 point

In a metal, electrons

can move freely

are confined to a single atom

always point in the same direction

do not exist

40.

1 point

Current is measured by:

amps

volts

watts

ohms

41.

1 point

What invention made it possible to change low voltage AC to high voltage AC?

samarium colbalt magnets

Van de Graaff generator

transformers

inverter

42.

1 point

the earth magnetism comes from

a dynamo in the core

iron in the crust

permanent magnets in the core

monopoles near the north and south geographic poles

43.

1 point

Most electric power is generated by

a wire moving through a magnetic field

moving a wire in a strong electric field

chemical means (batteries or fuel cells)

static electricity