For the given circuit,the reading of the ammeter in amperes is........

The current drawn from the battery in the given network is (Internal resistance of the battery is negligible). (in $A$)

$A$ uniform wire of length $200 \, cm$ is connected to a battery, two resistors and a galvanometer as shown in the figure. The galvanometer shows null deflection when the jockey $J$ is at $80 \, cm$ from point $A$. If the resistor $R_2$ is shunted with $30 \, \Omega$ resistance, the galvanometer shows null deflection when the jockey $J$ is at $100 \, cm$ from point $B$. Then the values of $R_1$ and $R_2$ respectively are

What is the equivalent resistance between $A$ and $B$ in the given circuit (in $\Omega$)?

If the Wheatstone bridge with four resistors $R_1, R_2, R_3$ and $R_4$ is balanced,then the correct expression is

The four arms of a Wheatstone bridge (Figure) have the following resistances: $AB = 100 \; \Omega$,$BC = 10 \; \Omega$,$CD = 5 \; \Omega$,and $DA = 60 \; \Omega$. $A$ galvanometer of $15 \; \Omega$ resistance is connected across $BD$. Calculate the current through the galvanometer when a potential difference of $10 \; V$ is maintained across $AC$.