How to make your own magnetic compass.

Find the area of the blades of the magnetic compass shown in the figure

A student performs an experiment to study the magnetic effect of current around a current carrying straight conductor with the help of a magnetic compass. He reports that The direction of deflection of the magnetic compass increases when the current through the conductor is increased. Which of the above observations of the student appears to be wrong and why?

A student performs an experiment to study the magnetic effect of current around a current carrying straight conductor with the help of a magnetic compass. He reports that For a given battery, the degree of deflection on N-pole decreases when the compass is kept at a point farther away firm the conductor. Is the given statement incorrect.

What is relative permeability of a magnetic material? How is it related to the magnetic susceptibility?

What is a magnetic compass? Explain it.