Explain it

05.06 — 1 short write-up

A checkpoint, not a test

Explain the focal-length crossing

Describe what the rays do, not only the memorized image labels.

In the lens or mirror lab, an object is moved from just outside the focal point to just inside it. Explain why the image changes from real and inverted to virtual and upright.

Compare whether the outgoing rays actually converge or spread and need backward extensions.