(i) Find the magnitude and direction of current in $1 \Omega$ resistor in the given circuit .
(ii) Two students X and Y perform an experiment on potentio meter separately using the circuit diagram shown below. Keeping other things unchanged (a) X increases the value of resistance R, (b) Y decrease the value of resistance S in the set up. How will these change affect the position of null point in each case and why ?
(a) Use Kirchhoff's rules , calculate the current in the arm AC of the given circuit ?
(b) On what principle does the meter bridge work ? Why are the metal strips used in the bridge ?