Calculate the effective resistance between $P$ and $Q$.

 

Three resistors of $3 \mathrm{\Omega }$ each are connected to a battery of $3 \mathrm{V}$ as shown. Calculate the current drawn from the battery.

In figure $R_1=10 \mathrm{\Omega }, R_{\mathit{2}}=20\mathit{ }\mathrm{\Omega }, R_3=25\mathit{ }\mathrm{\Omega }, R_4=5\mathit{ }\mathrm{\Omega }$ and a $12 \mathrm{V}$ battery is connected to the arrangement. Calculate:

(a) Total resistance in the circuit.

(b) Total current flowing in the circuit.

Two resistors of $30 \mathrm{\Omega }$ and $60 \mathrm{\Omega }$ are connected in parallel in an electric circuit. How does the current passing through the two resistors? compare.

In the circuit diagram shown, the two resistance wires A and B are of same length and same material, but A is thicker than B. Which ammeter $A_1$ or $A_2$ will indicate higher reading for current? Give reason.