Question

. A piece of wire of length X and resistance R has uniform cross-sectional area A. It is cut into four equal parts, then all the parts are connected in parallel to each other between P & Q in the circuit. Find:(i) Equivalent resistance R’.(ii) Ratio of R/r’
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Answer 1

Answer:

Resistance of a wire =

A

ρl

where, ρ is the resistivity of material of wire

l is length of wire

A is the cross sectional area of the wire.

⇒R=

A

ρl

⇒

A

ρ(L/4)

=

4

R

Thus, the four smaller wires have resistance R/4 each.

Now, these four resistances are connected in parallel.

Thus, effective resistance R

eff

is given by

⇒

R

eff

1

=

R/4

1

+

R/4

1

+

R/4

1

+

R/4

1

⇒R

off

=

16

R

Answer 2

Answer:

hope this helps you...