Some concepts need clarification. I am about to complete my 14 years and am in class 10th. 1. From my textbook : Take a magnetic needle freely pointing in north-south direction. Hold a thick insulated copper wire connected to battery above magnetic needle and close the circuit. It is observed that when current flows from south to north direction , the north pole of the needle points towards west as long as the current flows through wire. Similarly if current is flowing from north to south direction , the north pole of the magnetic needle deflects towards east. If wire is held below magnetic needle and current flowing from south to north , then magnetic needle deflects towards east. If current flows from north to south then magnetic needle deflects towards west. Q. Why does this happen ? How can I determine the direction in which magnetic needle deflects with respect to current flowing in particular direction ? Is there any concept behind it ? Why is magnetic field set up by a conductor acts at right angles to the direction of flow of current ? 2. From my textbook : Imagine you are holding the conductor with your palm such that fingers encircle the conductor showing direction of magnetic field and thumb shows the direction of current. This is Maxwell's Thumb Rule. Same way imagine a screw rotating , the linear distance showing the direction of current and rotation , the direction of magnetic field. This is Maxwell's Cork Screw Rule. Q. Suppose you have current flowing in this direction N ^ | | | S | South to north Then isn't it that the magnetic field will be in anticlockwise direction ? In one book it was shown that south to north flow of current is clockwise direction. Is it ? But by cork screw rule it shows opposite ! I am confused. Am I missing something ? Q. In an electromagnet , how will we determine that which end is north pole and which is south pole in a coil ? Q. Why is it that a magnetic field in a magnet starts from north pole and ends in south pole ? Why ?