# 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 | 1.0 | 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.

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,

Here,

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 5 A on a 220 V 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

this is done for x terms.

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