Chapter 11 · Electricity

NCERT Class 10 Science Chapter 11 Intext Questions (Page 185)

All 2 questions of NCERT Class 10 Science Chapter 11 Intext Questions (Page 185) — Electricity — in the book's order, each with its answer and a step-by-step solution.

1. Q1
   Draw a schematic diagram of ​a circuit consisting of a ​battery of three cells of 2 V each, ​a ​5 Ω ​resistor, an 8 Ω resistor, and a 12 Ω ​resistor, and ​a ​plug key, all connected in series.
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   All parts form one series loop, so the same current flows through the $5\Omega$, $8\Omega$ and $12\Omega$ resistors and the key.

   The circuit is a single closed loop, drawn in the figure. Going round it: the battery of three $2$ V cells, drawn as three long-plate-and-short-plate pairs all facing the same way and giving $2+2+2=6$ V; then the $5\Omega$ resistor, the $8\Omega$ resistor and the $12\Omega$ resistor, each shown as a zig-zag and labelled with its value; then the plug key, drawn closed as a small circle with a dot; and plain connecting wires joining them end to end with no branch anywhere. Since everything is in series there is only one path, so the same current flows through all three resistors and the key, leaving the positive terminal of the battery and returning to its negative terminal.

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2. Q2
   Redraw the circuit of ​Question 1, putting in ​an ammeter to ​measure the ​current ​through the resistors and a voltmeter to measure the potential difference ​across the 12 Ω ​resistor. What would ​be the readings in the ammeter and the voltmeter?
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   The ammeter reads 0.24 A and the voltmeter across the $12\Omega$ resistor reads 2.88 V.

   In the redrawn circuit the ammeter is cut into the loop itself, in series with the resistors so that the whole current passes through it, and the voltmeter is joined in parallel across the two ends of the $12\Omega$ resistor; each meter has its $+$ terminal on the side the current enters. The readings are: total resistance $R_s=5+8+12=25\Omega$; battery $V=3\times 2=6$ V; ammeter reading $I=V/R_s=6/25=0.24$ A; voltmeter reading $V_{12}=I{R}_3=0.24\times 12=2.88$ V. So the ammeter reads $0.24$ A and the voltmeter reads $2.88$ V.

   Step-by-step solution →