ARCH-P-03: Magnetic Flux Patterns & Motor Effect Force on Current-Carrying Conductors (F = BIL)

Full 15-Q Timed Drill

Step 1 of 6 • The Core Idea

ARCH-P-03: Why the 135s Classroom Method Fails Under the 90s Clock

Standard Classroom Method (Too Slow)~135s (Blows 90s Clock)

Convert time

t = 2 \times 60 = 120\text{ s}

, calculate current

I = \frac{Q}{t} = \frac{30}{120} = 0.25\text{ A}

, convert length

L = \frac{20}{100} = 0.2\text{ m}

, and evaluate

F = B I L = 0.40 \times 0.25 \times 0.2 = 0.02\text{ N}

(~120s).

The Fast ShortcutTarget: 35s (Saves 100s)

Line 1 (SI Grid):

F = B \left(\frac{Q}{60 t_{\text{min}}}\right) \left(\frac{L_{\text{cm}}}{100}\right)

.
Line 2 (Cancel Zeros):

F = 0.40 \times 0.25 \times 0.2 = 0.02\text{ N}

(25s).

Where Students Lose Time: In 9 past UAT-UK questions (3.86% of Physics), candidates lose 100s by pointing the second finger along electron velocity (- to +), reversing the magnetic force direction. Instead, apply P2 with Maths 1 skill M3.4.

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