NEET2013Physics-Current Electricity
NEET 2013 Physics Resistance and Resistivity MCQ Question
Type: MCQ-numerical-Hard-Class 12
Two rods are joined end to end, as shown. Both have a cross-sectional area of 0.01 cm². Each is 1 metre long. One rod is of copper with a resistivity of 1.7 × 10⁻⁶ Ω-centimetre, the other is of iron with a resistivity of 10⁻⁵ Ω-centimetre. How much voltage is required to produce a current of 1 ampere in the rods?
A
0.0045 V
B
0.0145 V
C
1.7 × 10⁻⁶ V
D
0.117 V
Correct Answer
Option B
Detailed Explanation
The total resistance R = R₁ + R₂, where R₁ and R₂ are the resistances of copper and iron rods respectively. Using R = ρL/A, calculate R₁ and R₂, then find the voltage using V = IR.
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