In the given circuit, $ E_{1}=E_{2}=E_{3}=2 \mathrm{~V} $ and $ R_{1}=R_{2}=4 \Omega $, then current flowing through the branch $ A B $ is

In the following circuit diagram, when $ 3 \Omega $ resistor is removed, then equivalent resistance of the network

A conducting wire is stretched by applying a deforming force, so that its diameter decreases to $ 40 \% $ of original value. The percentage change in its resistance will be

The power dissipated in the circuit shown in the figure $$40 \mathrm{~W}$$. The value of $$R$$ is.