Using the quarter‑wave length formula, what is the approximate length in feet for a frequency of 10 MHz?

Using the quarter‑wave length formula, what is the approximate length in feet for a frequency of 10 MHz?

• A. 23.4 ft
• B. 46.8 ft
• C. 11.7 ft
• D. 2.34 ft

Answer: (A)

Quarter-wavelength length follows from the relation L ≈ λ/4, with λ = c/f. For f = 10 MHz, λ ≈ (3.00 × 10^8 m/s) / (10 × 10^6 Hz) = 30 meters. A quarter of that is 7.5 meters. Converting to feet: 7.5 m × 3.28084 ft/m ≈ 24.6 ft. Among the options, 23.4 ft is the closest approximate value, which is why it’s the best choice for a quick, round-number estimate. The other options are noticeably farther from 24.6 ft.

Quarter-wavelength length follows from the relation L ≈ λ/4, with λ = c/f. For f = 10 MHz, λ ≈ (3.00 × 10^8 m/s) / (10 × 10^6 Hz) = 30 meters. A quarter of that is 7.5 meters. Converting to feet: 7.5 m × 3.28084 ft/m ≈ 24.6 ft. Among the options, 23.4 ft is the closest approximate value, which is why it’s the best choice for a quick, round-number estimate. The other options are noticeably farther from 24.6 ft.