S L Arora Solutions for Chapter: Current Electricity, Exercise 1: Problems For Practice

In a house having $220 \mathrm{V}$ line, the following appliances are working : (iii) a $40 \mathrm{W}$ radio. Calculate the current drawn by heater

In a house having $220 \mathrm{V}$ line, the following appliances are working : (iii) a $40 \mathrm{W}$ radio. Calculate the current passing through the fuse line.

Two bulbs rated $25 \mathrm{W}$, $220 \mathrm{V}$ and $100 \mathrm{W}$, $220 \mathrm{V}$ are connected in series to a $440 \mathrm{V}$ supply. What will happen if the two bulbs are connected in parallel to the same supply?

A series battery of $6$ lead accumulators, each of emf $2.0 \mathrm{V}$ and internal resistance $0.25 \mathrm{\Omega }$ is charged by a $230 \mathrm{V}$ d.c. mains. To limit the charging current, a series resistance of $53 \mathrm{\Omega }$ is used in the charging circuit. What is power dissipated as heat? Account for the difference in the two cases.

In the metre bridge experimental set up, shown in Fig, the null point '$D$' is obtained at a distance of $40 \mathrm{cm}$ from end $A$ of the metre bridge wire. If a resistance of $10 \mathrm{\Omega }$ is connected in series with $X$, null point is obtained at $AD=60 \mathrm{cm}$. Calculate the values of $X$ and $Y$.

In a metre-bridge experiment, two resistances $P$ and $Q$ are connected in series in the left gap. When the resistance in the right gap is $50 \mathrm{\Omega }$, the balance point is at the centre of the slide wire. It $P$ and $Q$ are connected in parallel in the left gap, the resistance in the right gap has to be changed to $12 \mathrm{\Omega }$ so as to obtain the balance point at the same position. Find $P$ and $Q$.

In a metre bridge when the resistance in the left gap is $2 \mathrm{\Omega }$ and an unknown resistance in the right gap, the balance point is obtained at $40 \mathrm{cm}$ iron the zero end on shunting the unknown resistance with $2 \mathrm{\Omega }$, find the shift of the balance point on the bridge wire.

Fig. shows experimental setup of a metre bridge. When the two unknown resistances $X$ and $Y$ are inserted, the null point $D$ is obtained $40 \mathrm{cm}$ from the end $A$. When a resistance of $10 \mathrm{\Omega }$ is connected in series with $X$, the null point shifts by $10 \mathrm{cm}$. Find the position of the null point when the $10 \mathrm{\Omega }$ resistance is instead connected in series with resistance '$Y$'. Determine the values of the resistances $X$ and $Y$.