Magnetic Fields (GCSE Physics)

A teacher demonstrates induction by moving a magnet into a coil connected to an ammeter; the needle deflects while the magnet moves and returns to zero when stationary. What principle does this show?

Which change will increase the magnetic field strength inside a solenoid?

A changing magnetic flux through a coil induces an emf. Which of these will NOT increase the induced emf in a coil?

Which of the following is a correct way to strengthen the magnetic field produced by an electromagnet?

Which of these will increase the voltage induced in a coil moved through a magnetic field?

Which arrangement will produce the strongest magnetic field outside a bar magnet?

Which factor does NOT affect the induced emf when a coil is rotated in a magnetic field?

An electromagnet’s coil is wound onto a soft iron core. If the current is switched off, why does the core lose most of its magnetism quickly?

Which property makes soft iron a suitable core for electromagnets used in transformers and relays?

What is the equation linking force (F), magnetic flux density (B), current (I) and length of wire (L) in a uniform magnetic field perpendicular to the wire?

Why does a transformer with a 2000-turn primary and a 40-turn secondary give a lower secondary voltage than primary?