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
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,
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.