ain with the HELP of a diagram how the INTENSITY and direction of the  magnetic field of a bar magnet can be determined. ❖ The intensity of magnetic field is indicated by the magnetic LINES of  force in that particular area. ❖ Intensity of magnetic field in a particular area can be understood by  the number of field lines passing perpendicular through that unit  area. ❖ The intensity of magnetic field is more where the lines of force are  more concentrated. ❖ The direction of magnetic field is determined by the directions of  magnetic lines of force. ❖ The magnetic lines of force always start from the north pole and end  on the south pole. ❖ In the similar manner, the direction of magnetic field is form north  pole to south pole.2. Why is a magnetic needle used in a compass? ❖ The magnetic needle used in a compass freely rotates and always  settles in the north-south direction as it is a property of a magnet❖ Thus, a magnetic needle can be used to ascertain the direction.  Hence, magnetic needle is used in a compass.3. Give DETAILED information about how the merchants of olden times used a magnet while travelling. ❖ The merchants of olden times used to carry compass for ascertaining  Directions while travelling. ❖ In a compass, a magnetic needle is fitted. This magnetic needle  supported on a sharp point can freely rotate in horizontal plane ❖ If a traveller goes ANYWHERE while travelling, due to the property  of a magnet, magnetic needle always get settled in the north-south  direction. ❖ Once, the north direction is known, other directions can be easily  known. ❖ At the oceans where only water is seen everywhere or at the desert  areas where only sand is seen everywhere, it becomes difficult to  know the direction at night. ❖ At that time, the compass used to be helpful for merchants to know  the directions.                     ____________