A current of $2\, mA$ was passed through an unknown resistor which dissipated a power of $4.4\, W$. Dissipated power when an ideal power supply of $11\, V$ is connected across it is
A$11\times10^{-5}\, W$
B$11\times10^{-3}\, W$
C$11\times10^{-4}\, W$
D$11\times10^{5}\, W$
JEE MAIN 2019, Medium
Download our app for free and get started
A$11\times10^{-5}\, W$
a $R =\frac{P}{l^{2}}=\frac{4.4}{4 \times 10^{-6}} \,\Omega $
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.*
Drift speed of electrons, when $1.5\, A$ of current flows in a copper wire of cross section $5\, mm^2$, is $v$. If the electron density in copper is $9 \times 10^{28}\, m^3$ the value of $v$ in $mm/s$ is close to (Take charge of electron to be $= 1.6 \times 10^{-19}\, C$)
A wire of resistance $R$ is bent to form a square $ABCD$ as shown in the figure. The effective resistance between $E$ and $C$ is ( $E$ is mid-point of arm $CD$ )
In Wheatstone's bridge $P = 9\, ohm$, $Q = 11\, ohm$, $R = 4\,ohm$ and $S = 6\,ohm$. How much resistance must be put in parallel to the resistance $S$ to balance the bridge ............... $ohm$
A cell of constant $e.m.f.$ first connected to a resistance ${R_1}$ and then connected to a resistance ${R_2}$. If power delivered in both cases is then the internal resistance of the cell is
Resistance are connected in a meter bridge circuit as shown in the figure. The balancing length $l_{1}$ is $40\,cm$. Now an unknown resistance $x$ is connected in series with $P$ and new balancing length is found to be $80\,cm$ measured from the same end. Then the value of $x$ will be $.......\Omega$
In a large building, there are $15$ bulbs of $40\ W$, $5$ bulbs of $100\ W, 5$ fans of $80\ W$ and $1$ heater of $1\ kW$. The voltage of electric mains is $220\ V$. The minimum capacity of the main fuse of the building will be ................ $A$