Rank the induced EMFs

Which change makes the EMF induced in a coil larger, with everything else unchanged?

Three induction runs sit in Zara's notebook. Which run induced the largest EMF? You can put the runs in order without a single measurement.

Here are Zara's three runs: the same coil, the same magnet, three different speeds.

In Trial 1, Zara pushed the magnet in at 5 cm/s. In Trial 2, she pushed it in at 2 cm/s. In Trial 3, she pushed it in at 10 cm/s.

Same coil, same magnet: only the speed differs.

The first step is to find the factor that differs between the trials. Here, only the speed differs.

The second step is to recall that factor's rule. Faster motion induces a bigger EMF.

The third step is to order the trials by that factor. Trial 3 is the fastest, then Trial 1, then Trial 2.

So the EMFs rank: Trial 3 largest, then Trial 1, then Trial 2 smallest.

The same three steps rank any set of runs that differ in one factor: find the factor, recall its rule, order by it.

You now hold three factor rules. Faster motion gives a bigger EMF. So does a stronger field. So does a coil with more turns.

The three factor rules, side by side.

Three coils are tested with the same magnet at the same speed. Coil P has 60 turns, coil Q has 15 turns, and coil R has 30 turns. Rank the coils from largest EMF to smallest.

Find the factor that differs: only the turn count differs.

Recall the rule: more turns give a bigger EMF.

Order by turns: coil P has 60, coil R has 30, coil Q has 15.

The ranking is coil P, then coil R, then coil Q.

Asha's three trials: the same coil and speed, with the weakest magnet, the strongest, and a middle one. Which factor differs?

Asha's trials: same coil, same speed; Trial 1 the weakest magnet, Trial 2 the strongest, Trial 3 a middle one. Which trial induces the largest EMF?

The same magnet enters the same 25-turn coil at 8 cm/s, then at 4 cm/s. Which run induces the larger EMF?

Only the speed differs between the runs.

Faster motion induces a bigger EMF, and 8 cm/s is faster than 4 cm/s.

The 8 cm/s run induces the larger EMF.

Mateo pushes the same magnet into the same coil at 3 cm/s, 12 cm/s, and 6 cm/s. Rank the pushes from largest EMF to smallest.

Your turn

Coil J has 12 turns, coil K has 48 turns, and coil L has 24 turns. The same magnet enters each at the same speed. Rank the coils from largest EMF to smallest.

Quinn pushes three magnets into the same coil at the same speed: a weak one, a very strong one, and a middling one. Rank the runs from largest EMF to smallest.

Asha gives the magnet a slow push, a medium push, and a fast push into the same coil. Rank the pushes from largest EMF to smallest.