When the resistance $R$ (indicated in the figure below) is changed from $1 \,k \Omega$. to $10 \,k \Omega$, the current flowing through the resistance $R'$ does not change. What is the value of the resistor $R'?$
KVPY 2021, Diffcult
Download our app for free and get started
(B)
Current through $R$ will not change only when wheatstone bridge is formed
$\Rightarrow \frac{1 K \Omega}{10 K \,\Omega}=\frac{ R ^{\prime}}{1 K \Omega}$
$\Rightarrow R ^{\prime}=100 \,\Omega$
Download our app
and 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.*
Two wires that are made up of two different materials whose specific resistance are in the ratio $2 : 3$, length $3 : 4$ and area $4 : 5$. The ratio of their resistances is
Carbon resistor has resistance specified by three bands having colour red, yellow and black. If this resistor is cut into two pieces of equal length then the new colour code of each one will be (Neglect tolerance of $4^{th}$ band)
An electric kettle has two heating coils. When one coil is used, water in the kettle boils in $5$ minutes, while when second coil is used, same water boils in $10\,\min$. If the two coils, connected in parallel are used simultaneously, the same water will boil in time
Shown in the figure below is a meter-bridge set up with null deflection in the galvanometer. The value of the unknown resistor $R$ is ............. $\Omega$
By error, a student places moving-coil voltmeter $V$ (nearly ideal) in series with the resistance in a circuit in order to read the current, as shown. The voltmeter reading will be ............ $V$
$A$ battery is of $\mathrm{emf}$ $E$ is being charged from a charger such that positive terminal of the battery is connected to terminal $A$ of charger and negative terminal of the battery is connected to terminal $B$ of charger. The internal resistance of the battery is $r$.