A copper wire has diameter 0.5 mm and re | Class 10 Science Chapter Electricity, Electricity NCERT Solutions

Question:

A copper wire has diameter 0.5 mm and resistivity of 1.6 × 10–8 Ω m. What will be the length of this wire to make its resistance 10 Ω? How much does the resistance change if the diameter is doubled?

Answer:

Resistance (R) of a copper wire of length l and cross-section A is given by the expression,

Where,

Resistivity of copper, p = 1.6 x 10-8 Ω m

Area of cross-section of the wire, 

Diameter = 0.5 mm = 0.0005 m

Resistance, R = 10 Ω

Hence, length of the wire,

If the diameter of the wire is doubled, new diameter = 2x0.5 = 1 mm = 0.001 m

Therefore, resistance R'

Therefore, the length of the wire is 122.7 m and the new resistance is 2.5 Ω


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Welcome to the NCERT Solutions for Class 10 Science - Chapter . This page offers a step-by-step solution to the specific question from Excercise 8 , Question 6: A copper wire has diameter 0.5 mm and resistivity of 1.6 × 10–8 Ω m. What will be ....