Electric circuits Grade 12
FSDOE 2014
Question 9
In the circuit represented below, the battery has an emf of 10 V and an unknown internal
resistance. Voltmeter V₁ is connected across the battery and voltmeter V2 is connected across the
open switch S. The resistance of the connecting wires and ammeter can be ignored.
V₁
emf = 10 V; r = ?
6 Ω
3 Ω
1Ω
Switch S is open.
9.1
What is the reading on V₁?
9.2
What is the reading on V₂?
V2
When switch S is closed, the reading on V₁ drops to 7,5 V.
9.3
What is the reading on V₂?
9.4
Calculate the reading on the ammeter.
9.5
Calculate the internal resistance of the battery.

9.6)Switch S is still closed,the 6 ohms resistor is removed:
what will happen to V1 reading?write down decrease,increase,remains the same.Explain your answer​