A hot electric iron has a resistance of $80\,\Omega $ and is used on a $200\, V$ source. The electrical energy spent, if it is used for two hours, will be ........... $Wh$
A$8000$
B$2000$
C$1000$
D$800$
Medium
Download our app for free and get started
C$1000$
c (c) Energy $\frac{{{V^2}}}{R}t = \frac{{200 \times 200 \times 2}}{{80}} = 1000\,Wh$
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 $6\,\,V$ battery is connected to the terminals of a $3\, m$ long uniform wire having resistance $100\,\Omega $. The difference in potential between two points on the wire separated by a distance of $50\, cm$ will be ............. $V$
Two uniform wires $A$ and $B$ are of the same metal and have equal masses. The radius of wire $A$ is twice that of wire $B$. The total resistance of A and $B$ when connected in parallel is
In a potentiometer wire experiment the $\mathrm{emf}$ of a battery in the primary circuit is $20\,V$ and its internal resistance is $5\,\Omega$ . There is a resistance box in series with the battery and the potentiometer wire, whose resistance can be varied from $120\,\Omega$ to $170\,\Omega$ . Resistance of the potentiometer wire is $75\,\Omega$ . The following potential differences can be measured using this potentiometer.
Four identical electrical lamps are labelled $1.5\,V$, $0.5\,A$ which describes the condition necessary for them to operate at normal brightness. A $12\,V$ battery of negligible internal resistance is connected to lamps as shown, then
Thousand cells of same emf $E$ and same internal resistance $r$ are connected in series in same order without an external resistance. The potential drop across $399$ cells is found to be ......... $E$
In the experimental setup of meter bridge shown in the figure, the null point is obtained at a distance of $40\,cm$ from $A$. If a $10\,\Omega $ resistor is connected in series with $R_1$, the null point shifts by $10\,cm$. The resistance that should be connected in parallel with $\left( {{R_1} + 10} \right)\,\Omega $ such that the null point shifts back to its initial position is .............. $\Omega$
In a building there are $15$ bulbs of $45\; \mathrm{W}, 15$ bulbs of $100\; \mathrm{W}, 15$ small fans of $10 \;\mathrm{W}$ and $2$ heaters of $1 \;\mathrm{kW}$. The voltage of electric main is $220\; \mathrm{V}$. The minimum fuse capacity (rated value) of the building will be: .......... $A$