Magnetic fields 0.0 / 5 PhysicsMagnetic fieldsA2/A-levelAQA Created by: argyrouCreated on: 30-04-18 22:47 In a magnetic field which direction do the field lines go? North to south 1 of 17 Define magnetic field Force field surrounding a magnet/current carrying wire placed in the field 2 of 17 What is the motor effect? When a current-carrying wire placed at a non-zero angle to the lines of force of an external magnetic field experiences a force due to the field, 3 of 17 What are the 4 factors that the magnitude of a force is dependent on? - current - strength of the magnetic field - length of the wire - angle between the lines of force of field and current direction 4 of 17 When is force greatest/at a maximum? When the wire is at right angles to the magnetic field 5 of 17 What is magnetic flux density B in words? Magnetic field strength. 6 of 17 What equation combines flux densitly, current and legth of wire? F=BIL 7 of 17 F=BIL only applies when B and I are at right angles to each other. How would you adapt the equation if the wire was at an angle to the field? F=BILsinX 8 of 17 Define torque of a couple in words When 2 forces are equal in magnitude but act in opposite directions 9 of 17 How would you adapt F=BIL when its for a coil rather than a wire in a magnetic field? F=BILn 10 of 17 What is the simple equation for the torque of a couple? torque of couple = Fd (d=perpendicular distance between line of action of forces on each side) 11 of 17 What is the torque of a couple when the coil is at an angle within the field? BIAncosX (where A=width x length and width comes from distance) 12 of 17 Define conventional current in terms of electron movement In opposite direction to the way in which electrons move 13 of 17 How does flux density B, charge and voltage link? F=BQV 14 of 17 What equation would you use to find the radius of a charged particle in a circular orbit? r=mv/BQ 15 of 17 What are the speed of particles when they exit from a cyclatron? v=BQR/m 16 of 17 What is the equation to find the time period of a charged particle in a circular orbit? T=2m /BQ 17 of 17

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