DZI Physics and Astronomy case studies
DZI Physics and Astronomy · Put your knowledge to work in context.
The DZI Physics and Astronomy credential is a multiple-choice assessment designed to test whether a candidate commands the core physics that underpins astronomical reasoning, from Newtonian mechanics through cosmology. It suits candidates preparing for graduate study or technical work in astronomy, physics teaching, science communication, or data-heavy research support, and it is also useful for self-directed learners who want an external check on breadth rather than depth in a single subfield. The DZI Physics and Astronomy case studies are 5 cases and about 2,644 words.
1Payload on a Rotating Tether: Tension and Release
A 1200 kg payload is attached to the end of a 2.0 km tether whose other end is anchored at the rim of a space station rotating with period 90 s. The payload orbits with the station at radius 60 m from the spin axis during the first test, then the tether is paid out to 2.0 km while the system is spun up so that the payload's tangential speed about the axis becomes 85 m/s.
577 words, about 3 min2Cooling a Detector Cryostat: Which Heat Leak Dominates?
A CCD detector sits inside a cryostat held at 120 K. The cryostat is surrounded by a 300 K radiation shield.
530 words, about 3 min3Interference Fringes from a Wedged Etalon
A student illuminates a thin glass wedge with a helium-neon laser at 632.8 nm and observes straight, equally spaced fringes on a screen. The wedge angle is nominally 2.0 × 10⁻⁴ rad, and the glass index is 1.52.
523 words, about 3 min4RC Filter Behavior with a Realistic Source Impedance
A student builds a low-pass RC filter with R = 10 kΩ and C = 10 nF, expecting a cutoff near 1.6 kHz. The source is a function generator with 600 Ω output impedance, and the load is an oscilloscope with 1 MΩ input in parallel with 15 pF.
490 words, about 2 min5Exoplanet Transit: Radius, Density, and a Stellar Puzzle
A transit survey observes a star of radius 1.1 R sun and mass 1.0 M sun with a periodic dip of depth 1.2% and duration 3.5 hours. Radial velocity follow-up gives a semi-amplitude of 12 m/s and a period of 4.2 days.
524 words, about 3 min