Answer:
Value of
is 7.466 ohm
Step-by-step explanation:
Let emf of the battery is e
In first case when only
is there current through battery is 2.2 A
So

......eqn 1
In second case current is reduced to 1.6 A when additional resistance of 2.8 ohm is added in series
So

....eqn 2
Fro eqn 1 and eqn 2



So value of
is 7.466 ohm