Find potential difference points $A \& F$ and $F \& B$.

Four $4 \Omega$ resistors are connected together along the edges of a square. A 12 V battery with internal resistance of $2 \Omega$ is connected across a pair of the diagonally opposite corners of the square. The power dissipated in the circuit is

A straight wire of mass 0.2 kg and length 1.5 m carries a current 2A is shown in the figure. It is suspended in mid-air by a uniform magnetic field $B$ pointing to the plane of paper. The magnitude of magnetic field is (ignore, earth's magnetic field and assume $g=10 \mathrm{~m} / \mathrm{s}^2$ )

The ratio of the magnetic field inside a solenoid at an axial point well inside and at an axial end point is