5.2 Resistance

Question 1

Resistance

Answer 1

Measures how much current is limited R = U/I

Question 2

Omhic resistor

Answer 2

A resistor that follows Ohm’s Law, meaning its voltage and current are directly proportional and its resistance remains constant.

Question 3

Ohms law

Answer 3

Voltage (across the wire) and current (through the wire) are directly proportional.

Question 4

Non-ohmic resistor

Answer 4

A resistor that does not follow Ohm’s Law; its voltage and current are not proportional, and its resistance can change with conditions like temperature.

Question 5

Proportional

Answer 5

When one value changes, the other changes by the same factor ( voltage doubles, current doubles)

Question 6

How to do calculations with resistance, voltage, current

Answer 6

Resistance: R= U/I
Voltage: U= I x R
Current: I= U/R

Question 7

NTC ( negative temperature coefficient)

Answer 7

A resistor whose resistance decreases as temperature increases. ( if T goes up, R goes down. Used as temperature sensor in circuits.

Question 8

PTC ( positive temperature coefficient)

Answer 8

A resistor whose resistance increases temperature increases. ( if T goes up, R goes up) used in overcurrent protection

Question 9

LDR ( Light dependent Resistor)

Answer 9

A resistor whose resistance decreases as light intensity increases. ( If light goes up, then R goes down) used in automatic lighting systems and light sensors.

Question 10

Variable resistor

Answer 10

A resistor whose resistance can be manually adjusted