In the circuit shown here, what is the value of the unknown resistor R so that the total resistance of the circuit between points P and Q is also equal to R 

(1) 3 ohms

(2) $\sqrt{39}ohms$

(3) $\sqrt{69}ohms$

(4) 10 ohms

Find the equivalent resistance between the points a and b 

(1) 2 Ω

(2) 4 Ω

(3) 8 Ω

(4) 16 Ω

The potential difference between points A and B is:

         
1. 207 V
2. 407 V
3. 107 V
4. 0

In the circuit shown in the figure, the current flowing in 2 Ω resistance 

(1) 1.4 A

(2) 1.2 A

(3) 0.4 A

(4) 1.0 A

In the figure given the value of X resistance will be, when the p.d. between B and D is zero 

(1) 4 ohm

(2) 6 ohm

(3) 8 ohm

(4) 9 ohm