PAU Physics (Aragón) case studies
PAU Physics (Aragón) · Put your knowledge to work in context.
This independent study page provides practice for PAU Physics (Aragón). Its editorial learning areas include Gravity; Electromagnetic Fields; Waves Optics; Modern Physics; Experimental Reasoning. The questions develop subject knowledge and application through worked reasoning, distinctions between competing answers, and practical scenarios. Study the relevant guide before attempting a mixed set, then explain the evidence or calculation that supports each answer. Topics on this exam: Gravity, Electromagnetic Fields, Waves Optics, Modern Physics, and Experimental Reasoning. The PAU Physics (Aragón) case studies are 4 cases and about 1,529 words.
1Resolving the Sodium Doublet: Which Order, and Is the Grating at Fault?
A student uses a plane transmission grating marked '500 lines per mm' and 10 mm wide to try to resolve the sodium doublet at 589.0 nm and 589.6 nm. A collimator produces a parallel beam that falls on the full width of the grating, and the diffracted light is observed through a telescope. In the second order the student records a single line at θ = 36.1°, sees no splitting anywhere in the pattern, and writes in the report: 'the doublet needs very high resolving power, so only the highest possible order can resolve it - the fourth order, m = 4, would give the best result. Since no split is seen, the grating must be defective.' The laboratory technician insists that the grating and the lamp are both satisfactory and that the fault lies in the optical arrangement.
699 words, about 3 min2Mass-spring measurements and an energy cross-check
A classroom group studies a horizontal cart attached to a spring on an idealized low-friction track. For this calculation the spring is massless, the track is level, friction is neglected and the restoring law is linear over all displacements used. The cart mass is 0.20 kg and the spring stiffness is supplied as 50 N/m. The group displaces the cart by 0.030 m from equilibrium and releases it from rest.
265 words, about 1 min3A loaded cell model and a changed external network
A theoretical direct-current source is modeled as an ideal electromotive force of 12.0 V in series with a fixed internal resistance of 1.0 ohm. Initially its external load is a 3.0 ohm resistor. Ideal ammeters have negligible resistance and an ideal voltmeter draws no current. A second calculation places a 6.0 ohm resistor in parallel with the original load while leaving the source model unchanged.
273 words, about 1 min4Comparing photon energy with a supplied work function
An idealized photoelectric experiment uses a clean hypothetical emitting surface with work function 2.30 eV. The surface name is deliberately unspecified: the work function is a supplied model parameter. Two narrow-band light sources have wavelengths 400 nm and 600 nm. For this exercise use hc = 1240 eV nm and the ordinary single-photon photoelectric model.
292 words, about 1 min