How does this potential divider circuit work?

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SUMMARY

The discussion centers on the operation of a potential divider circuit, specifically addressing how varying the resistance of a variable resistor influences the voltage across another resistor. It is established that altering the resistance affects the current flowing through the circuit, thereby changing the voltage distribution across the resistors. The correct answer to the posed question is option (B), as it accurately reflects the relationship between resistance and voltage in a potential divider setup.

PREREQUISITES
  • Understanding of Ohm's Law
  • Familiarity with potential divider circuits
  • Basic knowledge of electrical resistance and current
  • Concept of voltage division
NEXT STEPS
  • Study the principles of Ohm's Law in detail
  • Explore the design and applications of potential divider circuits
  • Learn about the effects of resistance on current flow in electrical circuits
  • Investigate practical examples of voltage division in real-world applications
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Electronics students, hobbyists experimenting with circuits, and engineers seeking to understand voltage regulation techniques.

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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
 
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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?
 

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