Physics B (Advancing Physics) - H557 考试技巧

计算器程序

常见错误

1. 1high涉及分数: 3Waves and quantum behaviour

   Assuming the wavelength of a standing wave is equal to the length of the wire or string instead of carefully determining the harmonic mode.

   如何避免: Always sketch the wave profile to identify nodes and antinodes. For the fundamental frequency on a fixed wire, the wavelength \(\lambda\) is twice the wire length (\(2L\)).
2. 2high涉及分数: 2Fundamental data analysis

   Failing to convert standard prefixed physical units (such as mm, ms, MeV, or u) into SI units before applying core equations.

   如何避免: Perform conversion steps at the very beginning of your calculation. Note down explicitly that 1 mm = 10^-3 m, 1 ms = 10^-3 s, and 1 u = 1.661 * 10^-27 kg.
3. 3medium涉及分数: 2Space, time and motion

   Resolving vector components with incorrect trigonometric functions (interchanging sine and cosine).

   如何避免: Trace out the vector triangle and use SOH CAH TOA explicitly. If resolving tension or velocity, verify whether the angle is relative to the horizontal or vertical axis.
4. 4medium涉及分数: 3Matter: hot or cold

   Attempting to explain enzyme-catalyzed digestive reactions using qualitative biological descriptions rather than thermodynamic Boltzmann distribution models.

   如何避免: Describe the enzyme action purely in terms of lowering the activation energy barrier, which increases the Boltzmann factor, representing a higher proportion of particles having energy >= activation energy.
5. 5high涉及分数: 2Fundamental data analysis

   Forgetting to set the calculator to Radian mode during diffraction grating or SHM calculations, or leaving it in Radian mode when resolving structural forces.

   如何避免: Develop a habit of checking the screen indicator (D vs R) before every exam segment. Use Degrees for force resolution and diffraction angle; use Radians for SHM equations and phase angles.
6. 6medium涉及分数: 1Out into space

   Omitting the negative sign in orbital gravitational potential energy calculations, leading to physical contradictions regarding system boundedness.

   如何避免: Use \(E_p = -\frac{GMm}{r}\). Retain the negative sign and add it directly to positive kinetic energy to establish a negative total orbital energy for bound satellites.
7. 7high涉及分数: 3Ionising radiation and risk

   Confusing the radioactive nuclei ratio left (N/N0) with the fraction that has decayed when evaluating elapsed decay times.

   如何避免: Read the text carefully. If one third of the original nuclei have decayed, then two thirds remain. Use \(N/N_0 = 2/3\) in the exponential decay equation, not \(1/3\).