Two linear parallel conductors carrying currents in the same direction attract each other and two linear parallel conductors carrying in opposite directions repel each other. The force acting per unit length due to currents \({ I }_{ 1 }and{ I }_{ 2 }\)in two linear parallel conductors held distance r apart in vacuum in SI unit is \(F=\frac { { \mu }_{ 0 } }{ 2\pi } \frac { 2{ I }_{ 1 }{ I }_{ 2 } }{ r } \)
Read the above passage and answer the following questions:
(i) What is the basic reason for the force between two linear parallel conductors currents?
(ii) Two straight wires A and B of lengths 2 cm and 20 cm, carrying currents  2.0 A and 5.0 A respectively in opposite directions are lying parallel to each other 4.0 cm apart. The wire A is held near the middle of wire B. What is the force on 20 cm long wire B?
(iii) What does this study imply in day to day life? 

When a galvanometer of resistance G is shunted with a low resistance S, then the effective resistance \({ Re }_{ ff }\)of galvanometer becomes
\( { Re }_{ ff }=\frac { GS }{ G+S } \)
If the current is passed through such a galvanometer, then the major amount of current flows through the shunt and the rest through the galvanometer, then the major amount of current flows through the shunt and the rest through galvanometer., the current divides itself in the inverse ratio of resistances.
Read the above passage and answer the following questions:
(i) Why is the resistance of shunted galvanometer lower than that of a shunt?
(ii) A galvanometer of resistance.\(30\Omega \) What the fraction of the main current passes (i) through the galvanometer and (ii) through the galvanometer and (ii) through the shunt?
(iii) What are the basic values you learn from the above study?

Saniya and Priya are friends. Both of them know that a small compass needle point always along north-south direction. One day Saniya is plotting field due to a bar magnet in the laboratory. She discovers a point where compass needle does not point along N-S. Rather, it sets itself in any arbitrary direction. Saniya thinks first that compass needle has become faulty. Priya then explains to her the real situation.
Read the above passage and answer the following questions:
(i) How did Priya justify the situation?
(ii) If a bar magnet is placed along the N-S direction with its north pole pointing north, what is the position of neutral points?
(iii) If a bar magnet is placed along N-S direction with its north pole pointing South, What is the position of neutral points?
(iv) What values of life do you learn from this piece of knowledge?