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Question
In the diagram shown alongside, the cell and the ammeter both have negligible resistance. The resistors are identical.
With the switch K open, the ammeter reads 0.6 A. What will be the ammeter reading when the switch is closed?
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Solution
Effective resistance = `1/R + 1/R`
Effective resistance = `2/R`
Current (I) = `V/(R/2)`
0.6 = `V/(R/2)`
`V/R` = 0.3 A
∴ Final current (I) = `V/(R/2)`
I = 0.9 A
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