A-LEVEL Physics: 5.3.4: Potential Divider Circuits (SaveMyExams)

Question 1

What happens when Two Resistors are Connected in Series? What is this proof of?

Answer 1

When Two Resistors are Connected in Series, The Potential Difference Across the Power Source is Divided Between them.
This is proof of Kirchoff’s Second Law.

Question 2

What are ‘Potential Dividers’?

Answer 2

Potential Dividers are Circuits which Produce an Output Voltage as a Fraction of the Input Voltage.

Question 3

Potential Dividers have 3 main purposes: (3)

Answer 3

-To Provide a Variable Potential Difference.

-To Enable a Specific Potential Difference to be Chosen.

-To Split the PD of a Source Between 2 or More Components.

Question 4

Potential Divider Equation:

Answer 4

Vout = R1 / (R1+R2) * Vin

Question 5

___ & ___ Resistors are Used in Potential Dividers to…

Answer 5

Variable, Sensory. To Vary the Output Voltage.

Question 6

Sensory Resistors Used in Potential Dividers: (2)

Answer 6

-Light Dependent Resistor (LDR)

-Thermistor

Question 7

The Resistance of an LDR is ___ Proportional to the Light Intensity.

Answer 7

Inversely.

Question 8

The Resistance of a Thermistor is ___ Proportional to the Temperature.

Answer 8

Inversely.

Question 9

If an LDR or Thermistor’s Resistance Decreases, its Potential Difference ___.

Answer 9

Decreases.

Question 10

If an LDR or Thermistor’s Resistance Increases, its Potential Difference ___.

Answer 10

Increases.

Question 11

For Potential Dividers, since Vtotal of the Components Must = Vin, if the PD of the Sensory Resistor Decreases, what must happen?

Answer 11

The PD of the Other Resistor in the Circuit Must Increase in Order to make Vtotal = Vin.

Question 12

For Potential Dividers, since Vtotal of the Components Must = Vin, if the PD of the Sensory Resistor Increases, what must happen?

Answer 12

The PD of the Other Resistor in the Circuit Must Decrease in Order to make Vtotal = Vin.

Question 13

In a Potential Divider, Due to Ohm’s Law, both the Resistor & Sensory Resistor are…
Hence, …

Answer 13

Connected in Series.
Hence, they have the Same Current.

Question 14

In a Potential Divider, if Resistance R Increases, what happens to the PD Across the Thermistor?

Answer 14

The PD Across the Thermistor Also Increases.

Question 15

In Series, the PD is Shared ___ Amongst the Components. Their Sum Equals the…

Answer 15

Equally.
= The EMF of the Power Supply. (Kirchoff’s Second Law)

Question 16

In a Potential Divider, if the PD Across the Thermistor Increases, what must happen? Why?

Answer 16

The PD Across the Resistor R Must Decrease, to keep the Same Overall Total EMF.