11.3 + 11.5 Electric Current & Electric Potential Difference

Question 1

A ______ is an object that lets
electrons move freely.

Answer 1

conductor

Question 2

An _____ ______ is defined as the
number of electrons moving in the same
direction past a certain point in one
second.

Answer 2

electric current

Question 3

in _______ ________ electrons actually move from the negative terminal to the positive.

Answer 3

conventional notation

Question 4

Electric current is measured in units
called _______

Answer 4

Amperes

Question 5

1 Ampere =

Answer 5

(1 Coulomb / second )

Question 6

Batteries supply direct current (DC)

Answer 6

The direct current supplied by a battery is in a fixed single direction and it doesn’t increase or decrease in magnitude.

Question 7

Wall sockets supply alternating current (AC).

Answer 7

the alternating current supplied by a wall socket periodically reverses direction in the circuit and the amount of current varies continuously

Question 8

An ________ is a device that measures
the amount of electric current in a circuit.
It is connected directly into the path of
the moving charges.

This type of connection is called a _____
connection.

Answer 8

Ammeter; series

Question 9

Ammeters are connected in _____ in the
circuit.

Answer 9

series

Question 10

________________ is a
measure of the amount of energy
per charge that is given to a load.

Answer 10

Electric potential drop

Question 11

___________ is a measure of the amount of energy per charge given by the source (battery).

Answer 11

Electric potential rise

Question 12

Both potential rise and potential drop are
represented by the symbol ΔV because
there is a __________

Answer 12

change in potential from one
side of a source or load to the other.

Question 13

ΔV is also called ____________.

Answer 13

“electric potential difference” or “voltage”

Question 14

The Electric Potential Difference (ΔV) is
defined as:

Answer 14

the change in electric potential when a charge is moved between two points in an electric field.

Question 15

The SI unit for electric potential difference is
the ____

Answer 15

volt (V)

Question 16

1 V =

Answer 16

1 J/C

Question 17

Electric potential difference between two
points in a circuit is measured with a device
called a _______.

Answer 17

voltmeter

Question 18

To measure electric potential difference, a voltmeter is connected across the source of electricity and the bulb in the circuit.

This type of connection is called a
______ connection.

Answer 18

parallel

Question 19

All of the electric potential _____ within
the circuit equal the total electric
potential _____ by the battery.

Answer 19

drops; gained

Question 20

Electricity is dangerous because of its effect
on the life support organs of the human body.
The primary factors determining the effect of
electricity on the body are the amount and
path of the ________ passing through the body.

Answer 20

current

Question 21

Currents of less than ___amp may produce
sensations ranging from tingling to sharp pain
or shock.

Answer 21

0.02

Question 22

A more serious effect occurs if the current
causes muscles to contract. A person touching
a live wire with their outstretched hand may
literally not be able to let go of the wire due to
the current’s effect on the muscles. Currents
from __________ amp will begin to impair the
ability of the person to breathe.

Answer 22

0.03 to 0.07

Question 23

The most dangerous range of currents is from
_______ amp. Currents in this range
can cause death by initiating fibrillation
(uncontrollable twitching) of the heart, which
stops the regular flow of blood to the rest of
the body.

Answer 23

0.1 to about 0.2

Question 24

Currents much larger than ____ amp
do not result in fibrillation - instead they __________.

Answer 24

0.1; stop the heart completely

Question 25

Because of the equation V = IR, we know that
Voltage and Resistance determine the ______.

Answer 25

current

Question 26

Therefore, high voltages and low resistance
will produce a high current, which is
_______

Answer 26

dangerous

Question 27

This is why electrical appliances warn against
use while in the shower or bath; although the
voltage of the appliance may not be sufficient
to send large currents through a dry body, the
same voltage may result in a very dangerous
current in a wet body. If the resistance of a
body is as low as ________, a voltage as
small as ______ can lead to fatal currents.

Answer 27

100 ohms; 20 volts