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

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

$A$ Wheatstone's bridge is balanced with a resistance of $625\, \Omega$ in the third arm, where $P, Q$ and $S$ are in the $1^{st}, 2^{nd}$ and $4^{th}$ arm respectively. If $P$ and $Q$ are interchanged, the resistance in the third arm has to be increased by $51\,\Omega$ to secure balance. The unknown resistance in the fourth arm is …………. $\Omega$

In a meter bridge experiment resistances are connected as shown in the figure. Initially resistance $P\, = 4\,\Omega $ and the neutral point $N$ is at $60\,cm$ from $A$. Now an unknown resistance $R$ is connected in series to $P$ and the new position of the neutral point is at $80\,cm$ from $A$ . The value of unknown resistance $R$ is

On interchanging the resistances, the balance point of a meter bridge shifts to the left by $10\ cm$. The resistance of their series combination is $1\ k\Omega$. How much was the resistance on the left slot before interchanging the resistances?  ………………  $\Omega$