(a) Define magnetic line of force.~(b) A wire of length 10 cm carrying a current of 4.0 A is placed between the poles of a powerful electromagnet of magnetic flux density 2.0 T. Calculate the:
(i) force on the wire when it is parallel to the field;
(ii) maximum force on the wire;
(iii) force on the wire when it makes an angle of 60° with the field.
(c) Describe how keepers can be used to preserve the magnetic strength of permanent bar magnets.
(d) A sailor observes that his mariners' compass reads N 10° W at a place where the angle of declination is N15° W. Calculate the true bearing of the place.~(c) Describe how keepers can be used to preserve the magnetic strength of permanent bar magnets.
(d) A sailor observes that his mariners' compass reads N 10° W at a place where the angle of declination is N15° W. Calculate the true bearing of the place.~(d) A sailor observes that his mariners' compass reads N 10° W at a place where the angle of declination is N15° W. Calculate the true bearing of the place.