In a given circuit, the cell P has an emf 1.5V and an unknown internal resistance while cell Q has an emf 2.0V and an internal resistance of 1 ohm if the ammeter reads 50m A, Then r is equal to
-
A.
0.5 ohm -
B.
0.62 ohm -
C.
1.0 ohm -
D.
2.0 ohm -
E.
3.0 ohm