Question

A copper wire has a diameter 0.5 mm
and resistivity 1.6X 10 ohmm.
(i) What will be the length of this wire to
make the resistance of 12 ohm.
(i) How much will be the resistance of another
copper wire of some length but half the
diameter ?
?​

Answer 1

Answer:

Explanation:diameter = 0.5 mm converting it into m

0.5× 1/1000=0.0005 m

Now (1)

R=rho l/a

12=16 ×l/0.0005

(Where l is the length of wire we have to find)

L=12×0.0005//16

L=3/4×0.0005

L=3×0.000125

L=0.000375 m

Or 0.375 mm

(2)

Diameter is half

A = pie (d/2)^2

A=pie d sq//4

Now new area

A'= pie (d/2×1/2)^2

A'=pie d sq//16

Or A'= A/4

Now if are is 1/4 then r will be 4 times as it is indirectly proportional to a

So the answer is= 12×4

=48 ohm

Hope it help

Answer 2

Explanation:

Here is your valuable answer

Thank You