Current Electricity

Ans3Internal resistance = Ext resistance so 2r=R
But wont P max be 2E^2 ÷R instead of E^2÷R

I am getting Pmax=(2E)^2÷(R+2r)
And 2r =R and so Pmax as 2E^2÷R

@SiddharthaGhosh
Pmax, which you have written is across the battery.......for across any resistor, Power is i^2R, where i is the current flowing through that resistor.

@SiddharthaGhosh
Check potential drop across R
It's E not 2E that's why.

@SiddharthaGhosh
You can find the max by am≥gm inequality if you don't know how to find maxima or minima of a function"Maximum power is dissipation takes accros the resistance when its value is equal to rest Equivalent resistance of the circuit..."