A heater of $220\, V$ heats a volume of water in $5\,\min$ time. A heater of $110\, V$ heats the same volume of water in ............... $min$
A$5$
B$8$
C$10$
D$20$
Easy
Download our app for free and get started
D$20$
d Heat produced $ = \frac{{{V^2}}}{R}t$
i.e. when voltage is halved, heat produced becomes one-fourth. Hence time taken to heat the water becomes four times.
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.*
A current of $0.1 \,A$ flows through a $25 \,\Omega$ resistor represented by the circuit diagram. The current in $80 \,\Omega$ resistor is ........... $A$
Six similar bulbs are connected as shown in the figure with a $DC$ source of $emf\; E$, and zero internal resistance. The ratio of power consumption by the bulbs when $(i)$ all are glowing and $(ii)$ in the situation when two from section $A$ and one from section $B$ are glowing, will be
The resistance of a heater coil is $110\, ohm$. A resistance $R$ is connected in parallel with it and the combination is joined in series with a resistance of $11\, ohm$ to a $220\, volt$ main line. The heater operates with a power of $110\, watt$. The value of $R$ in $ohm$ is
Four wires of equal length and of resistances $10$ $ ohms$ each are connected in the form of a square. The equivalent resistance between two opposite corners of the square is ............. $ohm$
$A$ wire of cross-section area $A$, length $L_1$, resistivity $\rho_1$ and temperature coefficient of resistivity $\alpha_1$ is connected to a second wire of length $L_2$, resistivity $\rho_2$ , temperature coefficient of resistivity $\alpha_1$ and the same area $A$, so that wire carries same current. Total resistance $R$ is independent of temperature for small temperature change if (Thermal expansion effect is negligible)