Paper 1 Q5 — Projectile in a uniform field

Uniform electric field — parabolic path of a charge; where it lands on the plate

What the examiners said

“Candidates found this question challenging. Many candidates chose incorrect option C, approximately ¾ of the way up the plate.”

Try the question (reconstruction)

A charged particle enters midway between two horizontal parallel plates, moving horizontally. It just grazes the far edge of the top plate as it leaves. Its vertical deflection follows y ∝ x². Relative to the entry point, where does it exit?

Examiner report: “Many chose ‘¾ of the way up’, picturing a straight diagonal instead of a parabola.”

Explore — parabola between the plates

Adjust the field strength and entry speed. The curve is y ∝ x². Compare it with the straight-line guess (dashed). Note how a parabola sits below the straight line for most of the journey.

Field / deflecting force: 5 Entry speed: 5

Same physics as a horizontally-thrown ball: uniform transverse force ⇒ parabolic path. Half-way along, only a quarter of the deflection has happened.

Original reconstruction inspired by the misconceptions described in the Singapore-Cambridge GCE A-Level H2 Physics 9749 November 2023 Examiner Report. Not the actual examination question. For classroom exploration.

Made by lookang, using Claude Fable 5. More resources: iwant2study.org