Wave speed formula for electromagnetic waves

Steps:

• Convert wavelength to meters: λ = 10 cm = 0.1 m.
• Apply formula f = c / λ, where c = 3.0 × 10^8 m/s.
• Compute: 3.0 × 10^8 / 0.1 = 3.0 × 10^9 Hz.
• This matches option A.

Why A is correct:

• Directly from c = f λ, frequency is speed divided by wavelength.

Why the others are wrong:

• B overestimates by factor of 10, as if λ = 0.01 m.
• C confuses frequency with speed value.
• D underestimates by factor of 100, as if λ = 10 m.

Final answer: A