In a meter bridge experiment null point is obtained at $40\, cm$ from one end of the wire when resistance $X$ is balanced against another resistance $Y$. If $X < Y$, then the new position of the null point from the same end, if one decides to balance a resistance of $3X$ against $Y$, will be close to .............. $cm$
JEE MAIN 2013, Diffcult
Download our app for free and get started
From question, $\frac{x}{y}=\frac{40}{100-40}=\frac{2}{3}$
$\Rightarrow x=\frac{2}{3} y$
Again, $\frac{3 x}{y}=\frac{z}{100-z}$
or $\frac{3 \times \frac{2 y}{3}}{y}=\frac{z}{100-z}$
Solving we get $Z=67\, \mathrm{cm}$
Therefore new position of null point
$\cong 67\, \mathrm{cm}$
Download our appand get started for free
Experience the future of education. Simply download our apps or reach out to us for more information. Let's shape the future of learning together!No signup needed.*
Similar Questions
- 1The current in a conductor varies with time t as $I = 2t + 3{t^2}$ where $I$ is in ampere and $t$ in seconds. Electric charge flowing through a section of the conductor during $t = 2\,\sec$ to $t = 3\,\sec$ is ............. $C$View Solution
- 2View SolutionAssertion : A current continues to flow in superconducting coil even after switch is off.
Reason : Superconducting coils show Meissner effect
- 3For the given circuit, in the steady state, $\left| V _{ B }- V _{ D }\right|=.......V.$View Solution
- 4$A$ battery consists of a variable number $n$ of identical cells having internal resistance connected in series. The terminals of the battery are short circuited and the current $I$ measured. Which one of the graph below shows the relationship between $I$ and $n$?View Solution
- 5Figure shows three similar lamp. $L_1,L_2$ and $L_3$ connected across a power supply. If the lamp $L_3$ fuses, how will the light emitted by $L_1$ and $L_2$ change ?View Solution
- 6If $X, Y$ and $Z$ in figure are identical lamps, which of the following changes to the brightnesses of the lamps occur when switch $S$ is closed?View Solution
- 7Two resistances are joined in parallel whose resultant is $\frac{6}{8}\,ohm$. One of the resistance wire is broken and the effective resistance becomes $2\,\Omega $. Then the resistance in ohm of the wire that got broken wasView Solution
- 8This question has Statement $1$ and Statement $2.$ Of the four choices given after the Statements, choose the one that best describes the two Statements.View Solution
Statement $1 :$ The possibility of an electric bulb fusing is higher at the time of switching $ON.$
Statement $2:$ Resistance of an electric bulb when it is not lit up is much smaller than when it is lit up.
- 9A house is served by $220\, V$ supply line in a circuit protected by a $9\, ampere$ fuse. The maximum number of $60\, W$ lamps in parallel that can be turned on, isView Solution
- 10The electric bulbs have tungsten filaments of same length. If one of them gives $60 \,watt$ and other $100\, watt$, thenView Solution