Two resistances are connected in two gaps of a meter bridge. The balance point is $20\, cm$ from the zero end. A resistance of $15\, ohms$ is connected in series with the smaller of the two. The null point shifts to $40\, cm$. The value of the smaller resistance in $ohms$ is

If the balance point is obtained at the $35^{th} cm$ in a meter bridge the resistances in the left and right gaps are in the ratio of

ln a balanced wheat stone bridge, current in the galvanometer is zero. It remains zero when:

$[1]$ battery emf is increased

$[2]$ all resistances are increased by $10\,ohms$

$[3]$ all resistances are made five times

$[4]$ the battery and the galvanometer are interchanged

In a balanced Wheatstone’s network, the resistances in the arms $Q$ and $S$ are interchanged. As a result of this

The current between $B$ and $D$ in the given figure is ………….. $amp$