Question

12. A manganin wire of resistivity 4.4 x 10 -5 m has a diameter of 0.4mm. What will be the
length of this wire to make the resistance of 4? How will the resistance change, if the diameter is
halved?

Answer 1

Answer:

Resistivity=ρ=

l

RA

=

2

70×π×(0.2×10

−3

)

2

=4.396×10

−6

Ωm

Answer 2

Answer:

4.396 × 10 -6 Sigma m

Explanation:

GIVEN- manganin wire of resistivity 4.4 x 10 -5 m has a diameter of 0.4mm

TO FIND- How will the resistance change, if the diameter is halved.

CONCEPT- p=I

SOLUTION- RA= 2 × 70 × π × ( 0.2× 10 × -3) × 2

= 4.396 × 10 -6 Sigma m

FINAL ANSWER- 4.396 × 10 -6 Sigma

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