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

Relation between Amp and Volts
I (amperes)0.51.02.03.04.0
V (volts)1.63.44.710.213.2

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

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.