Electromagnetism SAQ

North-seeking pole (or north pole) and south-seeking pole (or south pole)

A magnetic field

The direction a 'magnetic north' would travel in a magnetic field if free to do so

<p>By placing the bar magnet on a blank sheet of paper, positioning a plotting compass at one end of the magnet, and drawing dots at either end of the compass needle, then repeating this process and joining the dots.</p> Signup and view all the answers

<p>A giant bar magnet going through the centre of the Earth.</p> Signup and view all the answers

<p>The current flowing through the conductor.</p> Signup and view all the answers

<p>To determine the direction of the magnetic field around a conductor.</p> Signup and view all the answers

<p>By clasping the conductor with the right hand, with the thumb pointing in the direction of the current, and observing the direction of the fingers.</p> Signup and view all the answers

<p>A series of circles around the wire</p> Signup and view all the answers

<p>To set up a magnetic field when an electric current is passed through it</p> Signup and view all the answers

<p>Along the field lines from north to south</p> Signup and view all the answers

<p>A soft iron core with a coil of wire wound around it</p> Signup and view all the answers

<p>It disappears</p> Signup and view all the answers

<p>Newtons (N)</p> Signup and view all the answers

<p>F = IlB</p> Signup and view all the answers

<p>Fleming's left-hand rule</p> Signup and view all the answers

<p>current, length, and magnetic field</p> Signup and view all the answers

<p>perpendicular to each other</p> Signup and view all the answers

<p>The force experienced by a charged particle is directly proportional to the velocity of the particle and the magnetic flux density, as described by the equation F = qvB.</p> Signup and view all the answers

<p>Electromagnetic induction is based on the principle that a change in the magnetic flux linking a circuit induces an emf.</p> Signup and view all the answers

<p>The three components are the charge of the particle, its velocity, and the magnetic flux density of the field.</p> Signup and view all the answers

<p>The magnetic flux density determines the strength of the magnetic field, which in turn affects the force experienced by the charged particle.</p> Signup and view all the answers

<p>Magnetic flux (Φ)</p> Signup and view all the answers

<p>Φ = BA</p> Signup and view all the answers

<p>The magnitude of the induced emf is proportional to the rate of change of flux linking a circuit.</p> Signup and view all the answers

<p>Weber (Wb)</p> Signup and view all the answers

<p>Φ (phi)</p> Signup and view all the answers

<p>A generator converts mechanical energy into electrical energy by rotating a coil of wire within a magnetic field, causing flux to constantly change, thus inducing an EMF.</p> Signup and view all the answers

<p>An alternating current (a.c.) is an electric current whose direction reverses periodically, whereas a direct current (d.c.) is an electric current that flows continuously in the same direction.</p> Signup and view all the answers

<p>Lenz's law states that the direction of the induced emf is always such as to oppose the change causing it.</p> Signup and view all the answers

<p>The formula is E = -N (dΦ/dt), where E is the induced emf, N is the number of turns in the solenoid, Φ is the magnetic flux, and t is time.</p> Signup and view all the answers

<p>The negative sign indicates that the direction of the induced emf is always opposite to the direction of the change in magnetic flux, as stated by Lenz's law.</p> Signup and view all the answers

<p>The rms value is equal to the peak value divided by the square root of 2.</p> Signup and view all the answers

<p>V_rms = V_0 / √2</p> Signup and view all the answers

<p>The √2 accounts for the oscillating nature of the alternating current or voltage, allowing the rms value to be calculated as the square root of the peak value.</p> Signup and view all the answers

<p>The rms value is proportional to the peak value, with the proportionality constant being 1/√2.</p> Signup and view all the answers

<p>The rms value is a more useful value in many applications because it takes into account the oscillating nature of the alternating current or voltage, and is a better representation of the average value.</p> Signup and view all the answers

<p>Mutual induction, where a changing magnetic field in one coil induces an emf in another coil.</p> Signup and view all the answers

<p>To change the voltage of a.c. power supplies.</p> Signup and view all the answers

<p>Mutual induction.</p> Signup and view all the answers

<p>To change the voltage of a.c. power supplies in transformers.</p> Signup and view all the answers

<p>To step up or step down voltages.</p> Signup and view all the answers