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Question
Name three factors on which resistance of a given wire depends and state how is it affected by the factors stated by you.
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Solution
The following factors can affect a wire's resistance:
- Length of wire: The resistance increases as the wire length increases. R ∝ (l) (directly proportional).
- Area of cross-section (a): The area of the cross-section has an inverse relationship with resistance. For example, the resistance of a thick wire is lower than that of a thin one.
- Temperature (T): As the temperature rises, the resistance of the wire also rises.
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Exercise.
The values of current (I) flowing through a resistor for various potential differences V across the resistor are given below. What is the value of resistor?
| I (ampere) | 0.5 | 1.0 | 2.0 | 3.0 | 4.0 |
| V (volt) | 1.6 | 3.4 | 6.7 | 10.2 | 13.2 |
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