Standing wave antinodes in microwave cavity

Steps:

• In a standing wave, adjacent antinodes are separated by λ/2.
• The 6.0 cm (0.06 m) between melted sections is λ/2.
• Thus, wavelength λ = 2 × 0.06 m = 0.12 m.
• Frequency f = v/λ = (3.0 × 10^8 m/s) / 0.12 m = 2.5 × 10^9 Hz = 2.5 GHz.

Why C is correct:

• Antinode separation gives λ/2 = 0.06 m, so f = v/λ yields exactly 2.5 GHz via wave speed formula.

Why the others are wrong:

• A: 25 Hz implies λ ≈ 1.2 × 10^10 m, impossible for microwaves.
• B: 50 Hz implies λ ≈ 6 × 10^9 m, far too large.
• D: 5 GHz implies λ/2 = 0.03 m, but separation is 0.06 m.

Final answer: C