Essential Physics Formulas and Numerical Problem Solving

Posted by on May 11, 2026 in Secondary Education | 0 comments

1. Optics

Mirror and Lens Formulas

  • Mirror/Lens Formula: 1/f = 1/v + 1/u
  • Magnification: m = v/u = hi/ho
  • Power of Lens: P = 1/f (f in metres)
  • Combination of Lenses: Peq = P1 + P2 + …
  • Refractive Index: n = sin(i)/sin(r) = c/v
  • Critical Angle: sin C = 1/n

Numerical Tips

  • Always use sign conventions.
  • Convert focal length from cm to metres for power calculations.

2. Wave Optics

  • Fringe Width: β = (Dλ)/d
  • Bright Fringe Position: yn = nβ
  • Dark Fringe Position: yn = (2n – 1)β / 2
  • Diffraction Minimum: a sin θ = nλ
  • Resolving
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