$N$ sources of current with different emf’s are connected as shown in figure. The emf’s of the sources are proportional to their internal resistances,$\text{i.e.,} E=\alpha R,$ where $\mathrm{\alpha }$ is an assigned constant. The connecting wire resistance is negligible. The potential difference between points$A \text{and} B$dividing the circuit in $n$ and $N–n$ links.

 

The reading of voltmeter is

The current through the ammeter shown in figure is $1 \mathrm{A}.$ If each of the$4\mathrm{\Omega }$ resistor is replaced by $2\mathrm{\Omega }$ resistor, the current in circuit will become nearly :

The ammeter shown in figure consists of a$480 \mathrm{\Omega }$coil connected in parallel to a $20 \mathrm{\Omega }$ shunt. Find the reading of the ammeter.

The meter-bridge wire $AB$shown in figure is $50 \mathrm{cm}$ long. When $AD=30 \mathrm{cm}$, no deflection occurs in the galvanometer. Find$R$.