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The resistance of a wire is 10Omega. If ...

The resistance of a wire is `10Omega`. If it is stretched ten tmes, the resistance will be

A

`1Omega`

B

`10Omega`

C

`100 Omega`

D

`1000Omega`

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The correct Answer is:
To solve the problem of finding the new resistance of a wire when it is stretched ten times its original length, we can follow these steps: ### Step 1: Understand the relationship between resistance, length, and cross-sectional area The resistance \( R \) of a wire is given by the formula: \[ R = \frac{\rho L}{A} \] where: - \( R \) is the resistance, - \( \rho \) is the resistivity of the material, - \( L \) is the length of the wire, - \( A \) is the cross-sectional area of the wire. ### Step 2: Determine how stretching affects length and area When the wire is stretched to ten times its original length, the new length \( L' \) becomes: \[ L' = 10L \] As the wire is stretched, its volume remains constant. Therefore, if the original cross-sectional area is \( A \), the new cross-sectional area \( A' \) can be found using the volume conservation principle: \[ V = L \cdot A = L' \cdot A' \] Substituting \( L' \): \[ L \cdot A = 10L \cdot A' \] From this, we can derive: \[ A' = \frac{A}{10} \] ### Step 3: Calculate the new resistance Now, we can calculate the new resistance \( R' \) using the new length and area: \[ R' = \frac{\rho L'}{A'} = \frac{\rho (10L)}{\frac{A}{10}} = \frac{10 \rho L \cdot 10}{A} = 100 \cdot \frac{\rho L}{A} = 100R \] Given that the original resistance \( R \) is \( 10 \, \Omega \): \[ R' = 100 \times 10 \, \Omega = 1000 \, \Omega \] ### Final Answer: The new resistance of the wire after being stretched ten times its original length is \( 1000 \, \Omega \). ---

To solve the problem of finding the new resistance of a wire when it is stretched ten times its original length, we can follow these steps: ### Step 1: Understand the relationship between resistance, length, and cross-sectional area The resistance \( R \) of a wire is given by the formula: \[ R = \frac{\rho L}{A} \] ...
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