Electrical properties

Question 1

What is the unit of charge?

Answer 1

Coulomb (C)

Question 2

What does the Faraday constant represent?

Answer 2

The charge on 1 mole of electrons.

Question 3

What is the value of the Faraday constant?

Answer 3

9.648x10^4

Question 4

What is an electrical field?

Answer 4

A region where an electric force is experienced and can be mapped by electrostatic lines of force.

Question 5

What is the force on a charged body within an electric field dependent on?

Answer 5

• The charge on the body

- The strength or intensity of the field

Question 6

What is the unit of potential?

Answer 6

Volt

Question 7

What is a volt?

Answer 7

The potential difference between two points A and B is one volt if the work done in taking once coulomb of positive charge from B to A is one Joule.

Question 8

What is potential difference?

Answer 8

The difference in electrical potential between two points.

Question 9

What can be used to measure membrane potential?

Answer 9

A microelectrode and a reference electrode connected to a potentiometer.

Question 10

What are conductors?

Answer 10

Anything that can transmit charge.

Question 11

What are the conductors of biology?

Answer 11

Electrolyte solutions.

Question 12

What allows for conduction in metals?

Answer 12

Free electrons

Question 13

What does an electrical field do to free electrons?

Answer 13

Accelerates them so they drift in the direction of the field.

Question 14

What is the equation for calculating force?

Answer 14

F=1/r^2 (r=distance)

Question 15

What is the symbol for charge in an equation?

Answer 15

Q

Question 16

How do ion channels select between cations and anions?

Answer 16

Proteins comprised of negative amino acid side chains allow positive ions to pass through and vice versa.

Question 17

How does an increase in the number of charges affect potential?

Answer 17

Increases potential

Question 18

In what direction is a current carried?

Answer 18

From negative to positive

Question 19

What is a current?

Answer 19

The rate at which charge passes a point in a closed circuit.

Question 20

What is the unit of measurement for current?

Answer 20

Amperes (A)

Question 21

What is the symbol for current in an equation?

Answer 21

I

Question 22

What is resistance?

Answer 22

Opposition to flow through a conductor.

Question 23

What is the unit of measurement for resistance?

Answer 23

Ohms

Question 24

What is the symbol for resistance in equations?

Answer 24

R

Question 25

What is an electrical insulator?

Answer 25

A material that fully prevents current flow.

Question 26

What is conductance?

Answer 26

The ease with which a charge flows through a conductor.

Question 27

What is the unit of measurement for conductance?

Answer 27

Siemens

Question 28

What is the symbol for conductance in equations?

Answer 28

G or g

Question 29

What does Ohm's law quantify?

Answer 29

The relationship between potential difference (V), current (I) and resistance (R).

Question 30

What is the equation for Ohm's law?

Answer 30

V=IR

Question 31

What are capacitors?

Answer 31

Electrical devices that store charge.

Question 32

What is the simplest capacitor?

Answer 32

A parallel plate capacitor where the two plates are separated by a dielectric.

Question 33

How do capacitors work when connected to a battery?

Answer 33

- electrons flow form the negative terminal to plate A and at an equal rate from plate B to the positive terminal. - equal positive and negative charges build up on plates and start to oppose electron flow on plate A by repulsion and reduce flow from plate B by attraction. - charge accumulation on plates generates potential difference which increases to a value equal to that of the battery voltage - when potential difference across the capacitor (V) is equal to the battery voltage (Vo) electron flow ceases and the charging current equals 0.

Question 34

What is capacitance (C)?

Answer 34

The amount of charge a capacitor can store.

Question 35

What is the unit of measurement for capacitance?

Answer 35

Farads (F).

Question 36

What is capacitance proportional to?

Answer 36

- Surface area of the plates - increases with area. - Distance between plates - decreases with increased distance (d) - Properties of dielectric that separates the plates