Circuits And Resistance, REQ.PRAC

Question 1

A straight line through the origin indicates ..

Answer 1

Voltage and current are directly proportional, resistance is constant

Question 2

What does a steep gradient indicate

Answer 2

Low resistance

Question 3

What does a shallow gradient indicate

Answer 3

High resistance

Question 4

An Ohmic conductor is a resistor in which the current is..

Answer 4

Directly proportional to the potential difference at a constant temp
-indicated by a linear (straight line) graph

Question 5

As current though a filament lamp increases…

Answer 5

Temp increases, causes resistance to increase as current does
-indicates by a curved graph (s type of shape)

Question 6

Diode

Answer 6

Current through a diode only flows in ONE DIRECTION

• indicates by a horizontal line along x acid which shows no current flows
• so straight along x axis and then go diagonally up (as if it was directly proportional)

Question 7

A thermistor decreases as

Answer 7

Temp increases, useful in circuits where temp control is required

Question 8

The resistance of an LDR decreases as..

Answer 8

Light intensity increases, useful for automatic light control or detection (street light etc)

Question 9

Method of characteristics of a filament lamp, a diode and a resistor at a constant temp

Answer 9

1) set up standard test circuit
2) use variable resistor to adjust potential difference across text component
3) measure voltage and current for a range of voltage values
4) repeat experiment three times to calculate mean
5) repeat with other components

Question 10

Hazards of experiment

Answer 10

-filament lamp gets hotter as current increases and could cause burns

Question 11

Considerations

Answer 11

-before taking measurements, check voltage and current with supply turned off, this will allow zero errors to be made