Two identical batteries each of emf `E= 2`volt and internal resistance `r=1` ohm are available `t`. produce heat in an external resistance by passing a current through it. What is the maximum power that can be developed across an external resistance `R` using these batteries?

Options

A. 1.28Watt
B. 0.2 watt
C. `8/9 watt`
D. `3.2 watt`

Answer

B

Explanation

For maximum power in external resistance
`("External resistance")_("Net") = ("Internal resistance")`

Power in `R, P = i^(2)R = [(E)/(R+r//2)]^(2) R = (E^2)/(4R)`
`(2xx2)/(4xx0.5) = 2W`.