An ideal battery of $4\, V$ and resistance $R$ are connected in series in the primary circuit of a potentiometer of length $1\, m$ and resistance $5\,\Omega $ . The value of $R$, to give a difference of $5\, mV$ across $10\, cm$ of potentiometer wire, is: ................ $\Omega$
JEE MAIN 2019, Medium
Download our app for free and get started
$i=\frac{4}{5+R}$
$V_{A B}=i(5)=\frac{20}{5+R}$
$V_{A P}=\frac{V_{A B}}{L}(0.1)=\frac{20}{5+R}\left(\frac{0.1}{1}\right)=\frac{2}{5+R}$
Now, $\frac{2}{5+R}=5 \times 10^{-3}$
$\Rightarrow \quad R=395\, \Omega$
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
- 1Consider the circuit given here with the following parameters $E.M.F.$ of the cell = $12\, V$. Internal resistance of the cell $ = 2\,\Omega $. Resistance $R = 4\,\Omega $ Which one of the following statements in trueView Solution
- 2In a conductor $4$ coulombs of charge flows for $2$ seconds. The value of electric current will beView Solution
- 3View SolutionIt is easier to start a car engine on a hot day than on a cold day. This is because the internal resistance of the car battery
- 4A $9\, V$ battery with internal resistance of $0.5\,\Omega $ is connected across an infinite network as shown in the figure. All ammeters $A_1 , A_2, A_3$ and voltmeter $V$ are ideal. Choose correct statementView Solution
- 5Which of the following graphs represent the variation of power loss in the external load with external resistance $R$?View Solution
- 6In the figure given the value of $X$ resistance will be, when the $p.d.$ between $B$ and $D$ is zero ................... $ohm$View Solution
- 7Three $60\, W$ light bulbs are mistakenly wired in series and connected to a $120\,V$ power supply. Assume the light bulbs are rated for single connection to $120\,V$. With the mistaken connection, the power dissipated by each bulb is: .................. $W$View Solution
- 8An electric kettle has two heating coils. When one of the coils is connected to an a.c. sotuce, the water in the kettle boils in $10$ minutes. When the other coil is used the w’ater boils in $40$ minutes. If both the coils are connected in parallel, the time taken by the same quantity of water to boil will be ...... $min$View Solution
- 9View SolutionThe drift velocity does not depend upon
- 10In the circuit shown, the reading of the Ammeter is doubled after the switch is closed. Each resistor has a resistance $ = 1\,\Omega $ and the ideal cell has an $e.m.f. = 10\, V$. Then, the Ammeter has a coil resistance equal to ................ $\Omega$View Solution
