A heating coil is labelled $100\, W$, $220\, V$. The coil is cut in half and the two pieces are joined in parallel to the same source. The energy now liberated per second is .............. $J$
AIPMT 1995, Medium
Download our app for free and get started
(b) When the heating coil is cut into two equal parts and these parts are joined in parallel, the resistance of coil is reduced to one fourth, so power consumed will become $4$ times i.e. $400\, Js^{-1}.$
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 potentiometer $PQ$ is set up to compare two resistances as shown in the figure. The ameter $A$ in the circuit reads $1.0\, A$ when two way key $K_3$ is open. The balance point is at a length $l_1\, cm$ from $P$ when two way key $K_3$ is plugged in between $2$ and $1$ , while the balance point is at a length $l_2\, cm$ from $P$ when key $K_3$ is plugged in between $3$ and $1$ . The ratio of two resistances $\frac{{{R_1}}}{{{R_2}}}$ is found to be
A copper wire of length $10\,m$ and radius $\left(10^{-2} / \sqrt{\pi}\right) m$ has electrical resistance of $10 \,\Omega$. The current density in the wire for an electric field strength of $10( V / m )$ is :
Three resistors having resistances $\mathrm{r}_{1}, \mathrm{r}_{2}$ and $\mathrm{r}_{3}$ are connected as shown in the given circuit. The ratio $\frac{i_{3}}{i_{1}}$ of currents in terms of resistances used in the circuit is :
An electric kettle has two heating coils. When one of the coils is connected to an a.c. sotuce, the water in the kettle boils in $10$ minutes. When the other coil is used the w’ater boils in $40$ minutes. If both the coils are connected in parallel, the time taken by the same quantity of water to boil will be ...... $min$