Electricity HW

A 350-W hair dryer is operated on a 120-V circuit for 17 min. If electricity costs $0.10/kWh, what was the cost of using the blow dryer?

(350)(17/60 min)(.10) all over/ 1000 = .009 Round up to .01

The electric field lines in the diagram below indicate that

1 is a (+) charge and 2 is a (-) charge.

A lightbulb with a resistance of 6.0 Ω allows a 1.90 A current to flow when connected to a battery.

6.0 X 1.9 = 11.4 V; 11.4 X 1.9 = 21.7 W

An electric current is measured in units of

AMP

The electrical force is much weaker than the force of gravity.

False

Charge moving through a wire produces a magnetic field around the wire.

True

The attractive force between two unlike charges has the same strength as the repulsive force between two like charges.

True

If you steadily pushed the bar magnet through a coil of wire as shown,

a constant current would flow through the wire.

Electric field lines are drawn

in such a way as to show the direction of the field.

The north pole of a magnet is so named because

it points to the earth's north magnetic pole

A neutral atom gains one or more electrons and is now called a

negative ion

The size of a current in a conductor depends on the ________ as well as the voltage.

resistance

How is an unmagnetized piece of iron different from the same piece of iron when it is magnetized?

Magnetic domains are randomly oriented in unmagnetized iron, aligned in magnetized iron.

What causes an electron to move toward one end of a wire when the wire is moved across a magnetic field?

Electrons have magnetic fields that interact with an external magnetic field

Why does a balloon that has been rubbed stick to a wall for a while?

Friction transfers electrons to the balloon, which repels electrons in the wall, giving it a positive charge and opposite charges attract.

If you double the distance between two charged objects, you reduce the electrical force by a factor of four.

True

The north end of a suspended magnet will point to the magnetic north pole.

True

The volt is a measure of the work done by a battery as it forces a certain quantity of charges through a conductor.

True

What is a magnetic pole?

a side where the magnetic force seems to be concentrated

The magnitude of the resistance of a wire depends on

all of these are true

If you stopped the magnet midway through the loop,

the current would immediately drop to zero.

If you were to mechanically rotate the armature in an electric motor

the motor would behave like a generator.