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In a network as shown in the figure the ...

In a network as shown in the figure the potential difference across the resistance 2R is (the cell has an emf of E and has no internal resistance):

A

`( 7E) / (4R)`

B

`(4E)/7`

C

`(5E)/7`

D

8E

Text Solution

Verified by Experts

The correct Answer is:
C

`f = v (dm)/(dt) = 2(20) = 40 rArr f_(r) = mumg`
`m = 40 = M_(0) - 2(t) rArr t = 5 sec`
so `(0.1) (50 - 2t) = 40 rArr t = 5 sec`
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