How does this potential divider circuit work?

AI Thread Summary
Changing the resistance of a variable resistor in a potential divider circuit affects the current, which subsequently alters the voltage across the other resistor. The total voltage remains constant, but the ratio of voltages across the resistors changes based on the resistance values. When the variable resistor is reduced to zero, it creates a scenario where all voltage is dropped across the other resistor. This demonstrates the principle of voltage division, confirming that option (B) is correct. Understanding these relationships is crucial for analyzing potential divider circuits.
Dr. Who
Messages
9
Reaction score
0
Homework Statement
Below is an MCQ that appeared in a GCSE exam. I am confused about the solution. Please guide.
Relevant Equations
I= V/R (Ohm's Law)
Screenshot_20240226-063918~2.png

Screenshot_20240226-063948~2.png

The correct option is supposed to be (B). Can someone please explain why changing the resistance of the variable resistor affects the voltage across the other resistor? Also explain why (B) is the correct option? Thanks
 
Physics news on Phys.org
changing the resistance changes the current through the circuit, which in turn changes the voltages across the resistors. The TOTAL voltage across the two can't change but the ratio clearly changes. Think in extremes. What happens if the variable resistor is taken all the way to zero?
 
Thread 'Voltmeter readings for this circuit with switches'

Thread 'Voltmeter readings for this circuit with switches'

TL;DR Summary: I would like to know the voltmeter readings on the two resistors separately in the picture in the following cases , When one of the keys is closed When both of them are opened (Knowing that the battery has negligible internal resistance) My thoughts for the first case , one of them must be 12 volt while the other is 0 The second case we'll I think both voltmeter readings should be 12 volt since they are both parallel to the battery and they involve the key within what the...
View full post »
Thread 'Correct statement about a reservoir with an outlet pipe'

Thread 'Correct statement about a reservoir with an outlet pipe'

The answer to this question is statements (ii) and (iv) are correct. (i) This is FALSE because the speed of water in the tap is greater than speed at the water surface (ii) I don't even understand this statement. What does the "seal" part have to do with water flowing out? Won't the water still flow out through the tap until the tank is empty whether the reservoir is sealed or not? (iii) In my opinion, this statement would be correct. Increasing the gravitational potential energy of the...
View full post »

Similar threads

Understanding example in Wikipedia entry for open circuit voltage
Replies
3
Views
2K
Circuit with potential difference across battery being zero?
Replies
3
Views
1K
Ohm's Law - Finding Source Voltage
Replies
3
Views
1K
Finding Optimal Fixed Resistor for Potential Divider Circuit
Replies
45
Views
4K
Can a reed switch use a wheatstone bridge/potential divider?
Replies
1
Views
2K
Electric Potential Energy of Point Charge Systems
Replies
2
Views
964
Finding an open-cicuit voltage, why is resistor in series ignored?
Replies
2
Views
1K
Write boolean expression describing this circuit
Replies
4
Views
1K
Why do the headlights on the car become dim when the car is starting?
Replies
4
Views
2K
Sign conventions for Kirchhoff's loop rule
Replies
7
Views
2K

Hot Threads

Recent Insights

Back
Top