Light

  1. Q: Order the EM spectrum from longest λ → shortest λ.
    A: Radio → Microwave → Infrared → Visible → Ultraviolet → X-rays → Gamma

  2. Q: Which has the longest wavelength? Which has the shortest?
    A: Longest = Radio. Shortest = Gamma.

  3. Q: Visible light wavelength range (approx).
    A: ~400 nm (violet) to ~750 nm (red).

  4. Q: Match color → approx wavelength (nm).
    A: Red 750, Orange 650, Yellow 600, Green 550, Blue 500, Indigo 450, Violet 400.

  5. Q: Relationship between λ, ν, and E.
    A: λ ∝ 1/ν and E ∝ ν. So longer λ → lower ν → lower E; shorter λ → higher ν → higher E.

  6. Q: What is interference?
    A: When two or more waves overlap and combine — they can add or cancel.

  7. Q: Constructive interference — what and when?
    A: Waves in phase → amplitudes add → stronger signal.

  8. Q: Destructive interference — what and when?
    A: Waves out of phase → amplitudes subtract or cancel → weaker or zero signal.

  9. Q: Two equal waves 180° out of phase — result?
    A: Complete destructive interference (they cancel).

  10. Q: Which parts of the spectrum are ionizing?
    A: High-energy UV (upper UV), X-rays, and Gamma rays — can remove electrons.

  11. Q: Quick uses: what are X-rays and radio commonly used for?
    A: X-rays = medical imaging; Radio = communication, broadcasting.

  12. Q: Mnemonic to remember order (opinionated):
    A: “Really Mad In Vegas, Uber Xtra Gutsy” → Radio, Microwave, Infrared, Visible, Ultraviolet, X-ray, Gamma