The diagram shows a cell connected in series with an ammeter and three resistors (10 Ω, 20Ω, 30Ω). The circuit can be completed by a movable constant M. When M is connected to x, then ammeter reads 0.6 A. what is the ammeter reading when M is connected to y?
The current when it is connected to x is 0.6 A, so net resistance is 10 ohms so the cell voltage is 10 × 0.6 = 6 V.
Now when M is connected to y
the net resistance is sum of the resistance of 10 Ω and 20 Ω
Rnet=10+20=30 Ω
As we know by ohms law,
V=I R
Putting the values in the equation, we get
6 V= I× 30 Ω
I= = 0.2 A.
Thus, the reading of ammeter is 0.2 A.