12) 10th term of the Arithmetic Progression 2, -2, -6,? is

13) If the diameter of a finite length conductor reduces to half, then its resistance

14) Power factor of RC circuit is

15) Resistance of a copper wire is R. Four such wires with the same cross sectional area, but twice the length are connected in parallel, the net resistance is

16) Resistance of a galvanometer is 0.5 Ohm and full scale deflection corresponds to 10 mA. What is the shunt resistor required to increase the range of the instrument to 1 A.