Intro to Electricity

Question 1

Define Current

Answer 1

A flow of electric charge

Question 2

Define Voltage

Answer 2

Electric potential difference / potential difference in charge between two points in an electrical field

Question 3

Define Resistance

Answer 3

How a device reduces electrical current flow through it

Question 4

Define Capacitance

Answer 4

is a measure of the ability of a component

to store charge, measured in F (farad)

Question 5

What is Ohm’s Law

Answer 5

V = IR

Question 6

What does current flow in a circuit that contains a capacitor depend on?

Answer 6

Rate of change of voltage

Question 7

How to calculate total opposition to current flow in circuits that contain series networks of resistors?

Answer 7

1/CT = (1/C1) + (1/C2) +…..

Question 8

How to calculate total opposition to current flow in circuits that contain parallel networks of resistors?

Answer 8

CT= C1 + C2 +….

Question 9

Self-capacitance of a conductor is defined by

Answer 9

C= q/v

Question 10

All passive components have 3 electrical properties

Answer 10

Resistance, capacitance and inductance

Question 11

Basic capacitance properties

Answer 11

Q = CV
-> The charge Q is proportional to the voltage V across the capacitor and the proportionality constant is the capacitance C

Question 12

Model the neurone membrane

Answer 12

Lipid bilayer = capacitance
Channels = conductances
Ionic gradients = batteries

Question 13

The current through the conductive part of the membrane can be expressed as

Answer 13

a product of a conductance and a driving force:
I = g(V-Ee)
where V-Ee = driving force and g = conductance

Question 14

Siemens

Answer 14

1/ohm -> conductance

Question 15

V represents

Answer 15

Membrane potential

Question 16

Ee represents

Answer 16

Equilibrium potential of species e