Meter Bridge and Post Office Box

In a meter bridge balance point is found at a distance  $l_1$  with resistances R and S as shown in the figure.



When an unknown resistance X is connected in parallel with the resistance S, the balance point shifts to a distance $l_2$ . Find the expression for X in terms of  $l_1$ ,  $l_2$  and S.

Figure shows a Meter bridge wire $AC$ has uniform cross-section. The length of wire $AC$ is $100 \mathrm{cm}$ $X$ is a standard resistor of $4 \mathrm{\Omega }$ and $Y$ is a coil. When $Y$ is immersed in melting ice the null point is at $40 \mathrm{cm}$ from point $A$. When the coil $Y$  is heated to $100°\mathrm{C},$ a $12 \mathrm{\Omega }$ resistor has to beconnected in parallel with $Y$ in order to keep the bridge balanced at the same point. The temperature coefficient of resistance of the coil is $x\times {10}^{-2} \mathrm{SI}$ units. Find the value of $x$.

Consider the meter bridge circuit without neglecting end corrections. If we used $100 \mathrm{\Omega }$ and $200 \mathrm{\Omega }$ resistance in place of $R$ and $S$ respectively, we get null deflection at $l_1=33.0 \mathrm{cm}$. If we interchange the resistances, the null deflection was found to be at $l_2=67.0 \mathrm{cm}$. If $\alpha$ and $\beta$ are the end correction, then the value of $\alpha +\beta$ should be

If the wire in the experiment to determine the resistivity of a material using metre bridge is replaced by copper or hollow wire the balance point i.e. null point shifts to

Null method is superior over deflection method because

Where do we get the balancing point of the meter bridge generally?

Two resistances $\mathrm{X}$ and $\mathrm{Y}$ in the two gaps of a meter-bridge gives a null point dividing the wire in the ratio $2:3$. If each resistance is increased by $30 \mathrm{\Omega }$, the null point divides the wire in the ratio $5:6$, choose the correct value of $\mathrm{X}$ and $\mathrm{Y}$.

Where do we get the balancing point of the meter bridge generally?

With resistance $P$ and $Q$ in the left and the right gap respectively of a meter bridge, the null point divides the wire in the ratio $3:4$ . When $P$ and $Q$ are increased by $20 \mathrm{\Omega }$ each, the mull point divides the wire in the ratio $5:6$. Then the values of $P,Q$ respectively are ___.____

In a meter bridge (as shown below), the null point is found at a distance of $40 \mathrm{cm}$ from $A.$ If now a resistance of $12 \mathrm{\Omega }$ is connected in parallel with $S,$ the null point occurs at $60 \mathrm{cm}$ from $A.$ Determine the value of $R$(in $\mathrm{\Omega }$)

The figure shows a meter bridge wire $AC$ having uniform cross-section. The length of wire $AC$ is $100 \mathrm{cm}\text{.} X$ is a standard resistor of $4 \mathrm{\Omega }$ and $Y$ is a coil. When $Y$ is immersed in melting ice, the null point is at $40 \mathrm{cm}$ from point $A$. When the coil $Y$ is heated to $100°\mathrm{C}$, a $12 \mathrm{\Omega }$ resistor has to be connected in parallel with $Y$ in order to keep the bridge balanced at the same point. The temperature coefficient of resistance of the coil is $n\times$${10}^{-2}$ SI units. Find the value of $n$.

In a metre bridge experiment, null point is obtained at $20 \mathrm{cm}$ from one end of the wire when resistance $X$ is balanced against another resistance $Y$. If $X<Y$, then there will be the new position of the null point from the same end, if one decides to balance a resistance of $4 X$ against $Y$

In the following figure, a balanced meter bridge is shown. If the resistance of the wire of meter bridge is $1\mathrm{\Omega }/\mathrm{m}$, then find the value of resistance X and the current passing through the resistance X.

Two coils are connected in series in one gap of a meterbridge and the null point is obtained in the middle of the wire by putting $75\mathrm{\Omega }$ in the other gap. Two coils are then connected in parallel and the null point is obtained again in the middle of the wire , the resistance in the other gap is changed by $57\mathrm{\Omega }$. Find the resistance of each coil.

With an unknown resistance $\mathrm{X}$ in the left gap and a resistance of $30\mathrm{\Omega }$ in the right gap of meter-bridge the null point is obtained at $40 \mathrm{cm}$ from the left end of the wire. Find $\left(\mathrm{i}\right)$ the unknown resistance and $\left(\mathrm{ii}\right)$ the shift in the position of the null point  

(a) when the resistance in both the gaps are increased by $15\mathrm{\Omega }$ and

(b) when the resistance in each gap is shunted by a resistance of $8\mathrm{\Omega }$

In a post office box setup find the value of unknown resistance if the graph of galvanometer deflection versus $R$ for the ratio $100:1$ is given as shown

The diagram shows a modified meter bridge, which is used for measuring two unknown resistances at the same time. When only the first galvanometer is used, for obtaining the balance point, it is found at point $C$. Now, the first galvanometer is removed and the second galvanometer is used, which gives balance point at $D$. Using the details given in the diagram, find out the values of $R_1$ and $R_2$.

Cotyledons are also called-

What is the value of unknown resistance $R$, if galvanometer shows null deflection in the given meter bridge set up?

What happens to the balance point, When a metal conductor connected to left gap of a meter bridge is heated: