In the Wheatstone bridge circuit Fig. $5.149,$ the four arms have resistance $\mathrm{P}=2$ $\mathrm{\Omega }, \mathrm{Q}=4 \mathrm{\Omega }, \mathrm{R}=1 \mathrm{\Omega }$ and $\mathrm{S}=$
$3 \mathrm{\Omega }.$ The galvanometer $\mathrm{G}$ has the resistance $10 \mathrm{\Omega }$. Find the current through the galvanometer. What should be the value of $\mathrm{R}$ for the galvanometer current to be zero?

 

In the $\gamma$-connection, Fig. $5.149$(a), we see three resistances $R_1=10\Omega ,$ $R_2=12\Omega$ and $R_3=5\Omega .$ The terminals $A, B$ and $C$ 

are maintained at potentials $20 V, 10V$ and $15V$ respectively. Find the currents in the three resistances.

A metre bridge is balanced with a piece of aluminium wire of resistance $7.30 \Omega$ in the left-hand gap, the slide contact being $42.6 cm$ from the left-hand end of the bridge wire and the temperature was $17°C,$ If the temperature of the aluminium were raised to $57°C,$ how may the balance be restored.

(a) by adjusting the slide contact,   

Calculate the current drawn from the battery in the given network, shown in Figure

A $10 m$ Long wire of uniform cross-section of $20 \Omega$ Resistance is fitted in a potentiometer. This wire is connected in series with a battery of 5 $volts$ Along with an external resistance of $480 \Omega .$ If an unknown emf $\in$  Is balanced at $6.0 m$ Length of this wire, calculate 

(i) the potential gradient of the potentiometer wire,

A $10 m$ Long wire of uniform cross-section of $20 \Omega$ Resistance is fitted in a potentiometer. This wire is connected in series with a battery of $5 volts$ Along with an external resistance of $480 \Omega .$ If an unknown emf $\in$ Is balanced at $6.0 m$ Length of this wire, calculate 

(ii) the value of the unknown emf $\in .$