A battery with emf E and internal resistance r is connected to a variable load resistance R . To deliver the maximum possible power to the load, what value of R should be chosen? (Note that E and r cannot be changed.)
1
\(\boxed{R = 2r}.\)
2
\(\boxed{R = r}.\)
3
\(\boxed{R = r/2}.\)
4
\(\boxed{R >2r}.\)