# NCERT Class X Science Solutions: Chapter 12 – Electricity Part 3 (For CBSE, ICSE, IAS, NET, NRA 2022)

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Question 7:

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

 I (amperes) 0.5 1 2 3 4 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.

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

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.

According to Ohm՚s law,

Here,

Therefore,

Question 9:

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

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 5 A on a 220 V line?

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

this is done for x terms.

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

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