Question

6. A copper wire has diameter 0.5 mm and resistivity of 1.6 x 10'am. What will be
the length of this wire to make its resistance 10 07 How much does the resistance
change if the diameter is doubled?
7. The values of current I flowing in
corresponding values of
for​

Answer 1

6.

Given,

diameter of copper wire = 0.5mm = 5 × 10-⁴ m

resistivity = 1.6 × 10^-8 ohm.m

resistance = 10 ohm

Length = ?

we know,

R = dL/A

where R , d , L and A are resistance , resistivity , length and cross section area.

10 = 1.6 × 10^-8 × L/(πr²)

L = 10 × 3.14 × (2.5 × 10^-4)² × 10^8/1.6

L = 10× 3.14 × 6.25/1.6

L = 122.656 m

7.

Now if the diameter is doubled then the new resistance is R'=4ρL∕(π(2d)²) =4ρL∕(4πd²) =0.25R. Hence we see that the resistance of the wire becomes 25% of original resistance. This result is showing that the resistance decreases as we increase the cross-section area keeping the length constant.

8.

I am sorry But I didn't understand...

Explanation:

Hope its Help u..

and sorry for 8th