Problems for the 7th PYPT 2023

Released by the PYPT on 29 July 2022

Regional’s (Phase I)

1. Coloured Line (1)

When a compact disc or DVD is illuminated with light coming from a filament lamp in such a way that only rays with large angles of incidence are selected, a clear green line can be observed. The colour varies upon slightly changing the angle of the disc. Explain and investigate this phenomenon.

2.  Faraday Waves(7)

A droplet of less viscous liquid floating in a bath of a more viscous liquid develops surprising  wave-like patterns  when  the entire  system  is set  into  vertical  oscillation. Investigate this phenomenon and the parameters relevant to the production of stable patterns.

3. Upstream Flow (10)

Sprinkle light particles on a water surface. Then allow a water stream to be incident on the surface from a small height. Under certain conditions, the particles may begin to move up the stream. Investigate and explain this phenomenon.

4.  Rice Kettlebells(12)

Take a vessel and pour some granular material into it, for example, rice. If you dip e.g. a spoon into it, then at a certain depth of immersion, you can lift the vessel and contents by holding the spoon. Explain this phenomenon and explore the relevant parameters of the system.

5.  Pancake Rotation (15)

Place a few balls in a round container. If you move the container around a vertical axis, the balls can move co-directionally with the movement of the container, or they can move in the opposite direction. Explain this phenomenon and investigate how the direction of movement depends on relevant parameters.

6.  Arrester Bed (17)

A sand-filled lane results in the dissipation of the kinetic energy of a moving vehicle. What length is necessary for such an arrester bed to entirely stop a passively moving object (e.g. a ball)? What parameters does the length depend on?

No rejection allowed during Phase I Registration Open:

Last date of Registration: 14 Oct, 2022