3.12 Sensing

Question 1

Definition of current?

Answer 1

Rate of flow of charge

Question 2

What is the unit of charge?

Answer 2

Coulomb

Question 3

What device can be used to measure current?

Answer 3

Ammeter

Question 4

What direction does conventional current flow?

Answer 4

Positive to negative

Question 5

What direction do electrons flow and why?

Answer 5

Negatively charged so flow from negative to positive

Question 6

What is the definition of potential difference?

Answer 6

Energy transferred per unit charge

Question 7

What is the unit of potential difference?

Answer 7

Volts

Question 8

What device can we use to measure voltage across a component?

Answer 8

Voltemeter

Question 9

Definition of power?

Answer 9

Rate of transfer of energy

Question 10

What is the unit of resistance?

Answer 10

Ohms

Question 11

What can we think of resistance as?

Answer 11

A measure of how diffficult it is to get a current to flow through a component

Question 12

What is the equation for resistance?

Answer 12

R=V/I

Question 13

What is thr equation for conductance?

Answer 13

G=I/V

Question 14

What is the I-V characteristic?

Answer 14

A graph that show how current through a component changes as tgecpotential difference across it is increased

Question 15

How can we test the I-V charectitistic of acomppnent using a circuit?

Answer 15

1. set up circuit w component, voltemeter in parralel, ammeter in series and a variable resistor in series
2. Use variable resistor to alter PD and current measured through component and record V and I
3. Repeat to reduce random errors
4. Plot a graph of current against PD