Fields due to current carrying wires

• A long straight wire creates a magnetic field that obeys the right-hand grip rule and can be calculated using the equation B=2πaμo​I.
• When multiple wires are present, the resultant magnetic field can be calculated by using the above equation.
• The direction of the field can be determined using the right-hand grip rule.
• A solenoid creates a magnetic field that obeys the right-hand grip rule and can be calculated using the equation B=μo​nI.
• The strength of the field inside the solenoid is given by this equation.
• Using an iron core inside the solenoid will increase the strength of the magnetic field.
• When a current passes through a wire, it creates a magnetic field that obeys the right-hand grip rule and can be calculated using the equation B=2πaμo​I.
• If two parallel wires carry a current, they will each be in the other’s magnetic field, therefore a force will act on the wires.
• The direction of this magnetic field, due to wire X in the region of wire Y, will be out of the screen, according to the right-hand grip rule, and the strength can be calculated using B=2πaμo​IX​​.
• Wire Y will be carrying a current through this field and therefore will experience a force, F=BIl sinθ.
• Newton’s third law means that there will be an equal and opposite force on X towards Y.
• A compass needle is used to determine the direction of the magnetic field at any point by placing it parallel to the wire and observing its orientation relative to the north-south axis.