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Statement-1: The temperature dependence ...

Statement-1: The temperature dependence of resistance is usually given as `R=R_0(1+alphaDeltaT)`. The resistance of a wire changes from `100Omega to 150Omega` when its temperature is increased from `27^@C to 227^@C`. This implies that `alpha=2.5xx10^-3//^@C`.
Statement 2: `R=R_0(1+alphaDeltaT)` is valid only when the change in the temperature `DeltaT` is small and `DeltaR=(R-R_0) lt ltR_0`.

A

Statement-1 is true, Statement-2 is false

B

Statement-1 is true, Statement-2 is true, Statement-2 is the correct explaination of Statement-1

C

Statement-1 is true, Statement-2 is true, Statement-2 is not the correct explanation of Statement-1

D

Statement-1 is false, Statement-2 is true

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we will analyze both statements and derive the necessary calculations step by step. ### Step 1: Understand the given information We know that the resistance of a wire changes from \( R_0 = 100 \, \Omega \) to \( R = 150 \, \Omega \) when the temperature increases from \( T_0 = 27^\circ C \) to \( T = 227^\circ C \). ### Step 2: Calculate the change in resistance The change in resistance \( \Delta R \) can be calculated as: \[ \Delta R = R - R_0 = 150 \, \Omega - 100 \, \Omega = 50 \, \Omega \] ### Step 3: Calculate the change in temperature The change in temperature \( \Delta T \) is: \[ \Delta T = T - T_0 = 227^\circ C - 27^\circ C = 200^\circ C \] ### Step 4: Use the resistance-temperature relationship The relationship between resistance and temperature is given by: \[ R = R_0(1 + \alpha \Delta T) \] Substituting the known values: \[ 150 = 100(1 + \alpha \cdot 200) \] ### Step 5: Solve for \( \alpha \) Rearranging the equation: \[ 1 + \alpha \cdot 200 = \frac{150}{100} = 1.5 \] \[ \alpha \cdot 200 = 1.5 - 1 = 0.5 \] \[ \alpha = \frac{0.5}{200} = 2.5 \times 10^{-3} \, ^\circ C^{-1} \] ### Step 6: Analyze Statement 1 Statement 1 claims that the calculated value of \( \alpha = 2.5 \times 10^{-3} \, ^\circ C^{-1} \) is correct. However, we must check if the assumptions of the equation \( R = R_0(1 + \alpha \Delta T) \) hold true. ### Step 7: Check the validity of the equation The equation is valid only when: 1. The change in temperature \( \Delta T \) is small. 2. The change in resistance \( \Delta R \) is much less than \( R_0 \). In this case: - \( \Delta T = 200^\circ C \) is not small. - \( \Delta R = 50 \, \Omega \) is not much less than \( R_0 = 100 \, \Omega \). Thus, Statement 1 is **false**. ### Step 8: Analyze Statement 2 Statement 2 states that the equation \( R = R_0(1 + \alpha \Delta T) \) is valid only when \( \Delta T \) is small and \( \Delta R \ll R_0 \). Since we have established that these conditions are not met in this case, Statement 2 is **true**. ### Conclusion - Statement 1 is false. - Statement 2 is true. ### Final Answer - Statement 1: False - Statement 2: True ---
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