Narendra Kumar Solutions for Chapter: Magnetic Effects of Electric Current, Exercise 4: NCERT EXEMPLAR PROBLEMS

Why does a magnetic compass needle pointing North and South in the absence of a nearby magnet get deflected when a bar magnet or a current-carrying loop is brought near it? Describe some salient features of magnetic lines of field concept.

With the help of a labelled circuit diagram illustrate the pattern of field lines of the magnetic field around a current-carrying straight long conducting wire. How is the right hand thumb rule useful to find direction of magnetic field associated with a current-carrying conductor?

Explain with the help of a labelled diagram the distribution of the magnetic field due to a current through a circular loop. Why is it that if a current-carrying coil has $\mathrm{n}$ turns the field produced at any point is $\mathrm{n}$ times as large as that produced by a single turn?  

Describe the activity that shows that a current-carrying conductor experiences a force perpendicular to its length and the external magnetic field. How does Fleming’s left-hand rule help us to find the direction of the force acting on the current-carrying conductor?

Draw a labelled circuit diagram of a simple electric motor and explain its working. In what way these simple electric motors are different from commercial motors?

Explain the phenomenon of electromagnetic induction. Describe an experiment to show that a current is set up in a closed loop when an external magnetic field passing through the loop increases or decreases.

Describe the working of an AC generator with the help of a labelled circuit diagram. What changes must be made in the arrangement to convert it to a DC generator?

Draw an appropriate schematic diagram showing common domestic circuits and discuss the importance of fuse. Why is it that a burnt out fuse should be replaced by another fuse of identical rating?