A cell of internal resistance 2Ω supplies current to a 6Ω resistor. The efficiency of the cell is
a
12.0%
b
25.0%
c
33.3%
d
75.0%
Explanation
Correct Option
dVideo Explanation
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Discussions (15)

Richardq
7 years ago
for efficiency to be possible one needs to sum up both the internal resistance i.e (R+r) then the cumulative should be used to divide the external resistance and multiply by 100
(i.e efficiency= R/(R+r)*100.) that is it should be. efficiency=6/(6+2)*100 the right answer is 75%

Ojosamuel
8 years ago
The formula to use should be R/R+r × 100% not r/R × 100%
please reconsider, and feed me back
Thanks.

okraDEN2023
2 years ago
The answer is D.
Efficiency = IR/I(R+r) x 100 The current cancels out. Then
Efficiency = R/(R+r) x 100
= 6/(6+2) x 100
= 6/8 × 100
= 75%





