Read Induction Direction: Follow the Changing Flux
This short read prepares one exact NSEP pattern: lenz's law for a nearby current loop. Identify the physical condition before calculating.
Electricity questions depend on identifying charge, a conducting path and the condition that controls current or magnetic effect.
Start with the physical model
Read the configuration once, state the conserved quantity or governing law, and mark any changing geometry, sign convention or limiting condition.
Build the relation
The current in the straight wire follows the applied emf V(t)/R. From 0 to T/2 the current increases, so the magnetic flux through the nearby loop increases; from T/2 to T the current decreases, so the induced current reverses. Using the right-hand rule for the field of the straight wire and Lenz's law, the loop current is clockwise in the first half and anticlockwise in the second half.
Check before selecting
Check units, sign and one limiting case. A valid result must still fit the original geometry and stated constraint.
OlympIQ exam lens
- ✓Name the governing law before using a formula.
- ✓Keep the stated geometry and direction information explicit.
- ✓Use one unit or limiting-case check.
Use the change in flux, not the direction of the magnetic field alone, to apply Lenz's law.
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