When an ideal voltmeter is connected between the [points E and F the reading of the meter is `V_(0)`. When an ideal ammeter is connected between E and F, reading is `I_(0)` find the current I through resistor R connected between E and F.

Explanation

When an ammeter is put between E and F
`I_(0)=(V_(0))/(r+0)(thereforeR_(A)=0)impliesr=(V_(0))/(I_(0))`
When a resistance R is put between E and F
`I=(V_(0))/(R+r)=(V_(0))/(R(V_(0))/(I_(0)))=(V_(0)I_(0))/(V_(0)+I_(0)R)`