A $220 \; V , 50 \; Hz$ AC source is connected to a $25 \; V$, $5 \; W$ lamp and an additional resistance $R$ in series (as shown in figure) to run the lamp at its peak brightness, then the value of $R$ (in ohm) will be
  • A$975$
  • B$875$
  • C$775$
  • D$675$
JEE MAIN 2022, Medium
art

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.*

Similar Questions

  • 1
    In a potentiometer experiment two cells of $e.m.f.$ $E_1$ and $E_2$ are used in series and in conjunction and the balancing length is found to be $58\, cm$ of the wire. If the polarity of $E_2$ is reversed, then the balancing length becomes $29\, cm$. The ratio $\frac{{{E_1}}}{{{E_2}}}$ of the $e.m.f.$ of the two cells is
    View Solution
  • 2
    A meter bridge setup is shown in the figure. It is used to determine an unknown resistance $R$ using a given resistor of $15\,\Omega$. The galvanometer $(G)$ shows null deflection when tapping key is at $43\,cm$ mark from end $A$. If the end correction for end $A$ is $2\,cm$. then the determined value of $R$ will be__________ $\Omega$
    View Solution
  • 3
    Two wires $A$ and $B $ of same material and same mass have radius $2r$ and $r$ . If resistance of wire $A$ is $34\,\Omega $, then resistance of $B$ will be ............ $\Omega$
    View Solution
  • 4
    The internal resistance of a $2.1\, V$ cell which gives a current of $0.2\, A$ through a resistance of $10\,\Omega$ is ............. $\Omega$
    View Solution
  • 5
    At room temperature $\left(27^{\circ} \mathrm{C}\right)$, the resistance of a heating element is $50 \Omega$. The temperature coefficient of the material is $2.4 \times 10^{-4}{ }^{\circ} \mathrm{C}^1$. The temperature of the element, when its resistance is $62 \Omega$, is $\qquad$ ${ }^{\circ} \mathrm{C}$.
    View Solution
  • 6
    The current $I_{1}$ (in $A$) flowing through $1\; \Omega$ resistor in the following circuit is:
    View Solution
  • 7
    The specific resistance of a wire is $\rho $, its volume is $3\,{m^3}$ and its resistance is $3\, ohms$, then its length will be
    View Solution
  • 8
    If ${R_1}$ and ${R_2}$ are respectively the filament resistances of a $200$ $watt$ bulb and $100$ $watt$ bulb designed to operate on the same voltage, then
    View Solution
  • 9
    In the experiment of calibration of voltmeter, a standard cell of $e.m.f\,\,1.1\,volt$ is balanced against $440\,cm$ of potential wire. The potential difference across the ends of resistance is found to balance against $220\,cm$ of the wire. The corresponding reading of voltmeter is $0.5\,volt.$ The error in the reading of volmeter will be .................. $volt$
    View Solution
  • 10
    If a $30\, V$, $90\, W$ bulb is to be worked on a $120\, V$ line, a resistance of how many ohms should be connected in series with the bulb ............... $ohm$
    View Solution