Looking for a light challenge?

Polytechnic University runs the annual Senior Secondary Science and Mathematics Competitions in April each year to promote students' interest in maths, physics, chemistry and biology. Entries for this year's competition have already closed, but you can still get a taste of what it involves.

Young Post will be running sample questions on a different topic every week. More questions can be found on yp.scmp.com. The answers will be published the following week, as well as questions on a new topic.

This week, we feature two sample physics questions. Challenge yourself, and check the answers online next week.

1 An object is placed between the focal point and a location at twice the focal length along the optic axis of a converging lens. The image formed will be:

a. Real and upright

b. Real and inverted

c. Virtual and upright

d. Virtual and inverted

2 Sunlight (electromagnetic waves) passes through a crystal and emerges with the electric field oscillating in only one plane perpendicular to the direction of propagation. This demonstrates the phenomenon of:

a. Diffraction

b. Refraction

c. Interference

d. Polarisation