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A piece of wire of resistance R is cut i...

A piece of wire of resistance R is cut into five equal parts. These parts are then connected in parallel. If the equivalent resistance of this combination is R., then the ratio `R/(R.)` is ………………. .

A

`1/25`

B

`1/5`

C

`5`

D

`25`

Text Solution

Verified by Experts

The correct Answer is:
D
Here, the resistance of a piece of wire is R. This piece of wire is cut into five equal parts, so the resistance of each part would be `R/5`.
Now, these five parts each having resistance of `R/5` are connected in parallel.
The equivalent resistance R. of this combination is given by
`1/(R.) =(1)/(R/5) + 1/(R/5) +1/(R/5) +1/(R/5) +1/(R/5)`
`:. 1/(R.) = 5/R + 5/R +5/R + 5/R +5/R = (25)/R`
`:.R/(R.) =2 5`
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