NCERT Class X Science Solutions: Chapter 12 – Electricity Part 3

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Question 7:

The values of current I flowing in a given resistor for the corresponding values of potential difference V across the resistor are given

Relation between Amp and Volts
Relation between Amp and Volts

I (amperes)

0.5

1.0

2.0

3.0

4.0

V(volts)

1.6

3.4

4.7

10.2

13.2

Plot a graph between V and I and calculate the resistance of that resistor.

Answer:

The plot between voltage and current is called characteristic. The voltage is plotted on x-axis and current is plotted on y-axis.

Plotting amp vs volts

Plotting Amp vs Volts

The slope of the line gives the value of resistance (R)

𝑠𝑙𝑜𝑝𝑒

Question 8:

When a battery is connected across an unknown resistor, there is a current of in the circuit. Find the value of the resistance of the resistor.

Answer:

According to Ohm’s law,

Therefore,

Question 9:

A battery of is connected in series with resistors of respectively. How much current would flow through the resistor?

Answer:

Total resistance of resistors when connected in series is given by

According to Ohm’s law,

There is no current division occurring in a series circuit. So, the current through the resistor will be same as

Question 10:

How many resistors (in parallel) are required to carry line?

Answer:

Let the total number of resistors be x.

Given that:

Current and Potential Difference

According to Ohm’s law,

Now for x number of resistors of resistance, the equivalent resistance of the resistors connected in parallel is

Therefore, 4 resistors of are required to draw the given amount of current.

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