An electric bulb rated as $200\, {W}$ at $100 \,{V}$ is used in a circuit having $200\, {V}$ supply. The resistance $'R'$ that must be put in series with the bulb so that the bulb delivers the same power is $.....\,\Omega$
To produce same power, same voltage should be across the bulb
Hence, $R=R_{B}=50 \Omega$
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$A$ conductor is made of an isotropic material and has shape of a truncated cone. $A$ battery of constant emf is connected across it and its left end is earthed as shown in figure. If at a section distant $x$ from left end, electric field intensity, potential and the rate of generation of heat per unit length are $E, V$ and $H$ respectively, which of the following graphs is are correct?
When the resistance of $9 \,\Omega$ is connected at the ends of a battery, its potential difference decreases from $40\, volt$ to $30\, volt$. The internal resistance of the battery is ............... $\Omega$
In a potentiometer circuit a cell of $EMF$ $1.5\, {V}$ gives balance point at $36\, {cm}$ length of wire. If another cell of $EMF$ $2.5\, {V}$ replaces the first cell, then at what length of the wire, the balance point occurs ? (in $cm$)
In a potentiometer (see figure) a balance is obtained at a length of $400\ mm$ when using a known battery of emf $1.6\ V$. After removing this battery, another battery of unknown emf is used and balance is obtained at a length of $650\ mm.$ The emf of unknown battery is ............. $volt$
The resistance in the two arms of a meter bridge are $5\,\Omega $ and $R\,\Omega $, respectively. When the resistance $R$ is shunted with an equal resistance, the new balance point is at $1.6\, l_1$. The resistance $‘R’$ is ................. $\Omega$
A potentiometer is connected between $A$ and $B$ and the balance point is obtained at $203. 6\,cm$. When the end of the potentiometer connected to $B$ is shifted to $C$, then the balance point is obtained at $24.6\,cm$. If now the potentiometer be connected between $B$ and $C$, the balance point will be at ................. $cm$
Two $220\; V , 100 \;W$ bulbs are connected first in series and then in parallel. Each time the combination is connected to a $220 \;V \;AC$ supply line. The power drawn by the combination in each case respectively will be