Question 22M.2.HL.TZ1.8c.i
| Date | May 2022 | Marks available | [Maximum mark: 2] | Reference code | 22M.2.HL.TZ1.8c.i |
| Level | HL | Paper | 2 | Time zone | TZ1 |
| Command term | Explain | Question number | c.i | Adapted from | N/A |
Two capacitors C1 and C2 of capacitance 28 µF and 22 µF respectively are connected in a circuit with a two-way switch and a cell of emf 1.5 V with a negligible internal resistance. The capacitors are initially uncharged. The switch is then connected to position A.
A cell is now connected by a switch to a coil X. A second coil Y of cross-sectional area 6.4 cm2 with 5 turns is looped around coil X and connected to an ideal voltmeter.
The switch is closed at time t = 0. Explain how the voltmeter reading varies after the switch is closed.
[2]
initial deflection by voltmeter falling to zero reading ✓
emf is induced «only» while the field / flux is changing ✓
This question was well answered by some candidates who recognized that it was an electromagnetic induction question and understood that eventually the current in coil X would hit a steady state and the voltmeter reading would return to zero. Common issues were candidates thinking that the potential would fluctuate in a manner similar to an alternating current, candidates discussing this more as a transformer, and candidates who missed that there were two separate coils and wrote responses suggesting that a simple circuit had been formed and the voltmeter would read the potential of the cell.
