Wheat Stone Bridge Excercise

 Question 1 : For the Following Bridge confirm if 

1. The following Bridge is balanced ?

2. The value of Vout

3. Which resistor should be used at R4 to balance bridge

 

Question 2 

A circuit consists of two resistors with resistances R1 = 160 Ω and R2 = 15 Ω , a variable resistor, which can be adjusted, and 25 v volt battery connected as shown in the figure. When Rvar is adjusted to 12 ohms, there is zero current through the ammeter. What is the unknown resistance Ru ?

Also Confirm the Current value  mathematically , that will be shown by ammeter if the bridge is balanced