A slit of width 1 × 10⁻⁵ m is illuminated by light of wavelength 500 nm. The angular position of the first minimum (in radians, small angle) is approximately:

First minimum: sin θ ≈ θ = λ/a = (500 × 10⁻⁹) / (1 × 10⁻⁵) = **0.05** — wait, 5 × 10⁻². Let me recompute: 5 × 10⁻⁷ / 1 × 10⁻⁵ = 5 × 10⁻² = **0.05 rad ≈ 2.86°**. So A is correct.