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Course: Class 12 Physics (India) > Unit 3

Lesson 5: Cell, EMF, terminal voltage, & internal resistance
Science
Class 12 Physics (India)
Current electricity
Cell, EMF, terminal voltage, & internal resistance
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Cells: emf and internal resistance

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Problem

An external resistance, R=22 Ω, is connected through a switch to a cell of emf, E=12 V, and internal resistance, r=2.0 Ω.
A voltmeter is connected across the cell.
What is the voltmeter reading when -
(a) the circuit is open (switch OFF)?
  • Your answer should be
  • an integer, like 6
  • a simplified proper fraction, like 3/5
  • a simplified improper fraction, like 7/4
  • a mixed number, like 1 3/4
  • an exact decimal, like 0.75
  • a multiple of pi, like 12 pi or 2/3 pi
V
(b) the circuit is closed (switch ON)?
  • Your answer should be
  • an integer, like 6
  • a simplified proper fraction, like 3/5
  • a simplified improper fraction, like 7/4
  • a mixed number, like 1 3/4
  • an exact decimal, like 0.75
  • a multiple of pi, like 12 pi or 2/3 pi
V