Current Electricity and Electrical InstrumentMedium
Question
Two wires of same metal have the same length but their cross sections are Anthe ratio 3 : 1. They are joined in series. The resistance of the thicker wire is 10Ω . The total resistance of the combination is
Options
A.5/2 Ω
B.40/3 Ω
C.40 Ω
D.100 Ω
Solution
Resistance of a wire = ρl/A
For the same length and same material,
or, R2 = 3R1
The resistance of thick wire, R1 = 10Ω
The resistance of thin wire = 3R1 = 3 × 10
= 30 Ω
Total resistance = 10 + 30 = 40 Ω
For the same length and same material,
or, R2 = 3R1The resistance of thick wire, R1 = 10Ω
The resistance of thin wire = 3R1 = 3 × 10
= 30 Ω
Total resistance = 10 + 30 = 40 Ω
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