Which quantity's units result from multiplying wavelength by frequency?

Which quantity's units result from multiplying wavelength by frequency?

• A. Velocity
• B. Mass
• C. Acceleration
• D. Power

Answer: (A)

The key idea is the wave relationship v = λ f, which connects how far a wave travels per unit time to its wavelength and frequency. Wavelength is measured in meters and frequency in s⁻¹ (per second). Multiplying them gives meters times per second, or m/s, which are the units of velocity. So the product directly yields a quantity describing how fast something travels, i.e., velocity. The other options have different units: mass is kilograms, acceleration is meters per second squared, and power is joules per second (watts); none match m/s.

The key idea is the wave relationship v = λ f, which connects how far a wave travels per unit time to its wavelength and frequency. Wavelength is measured in meters and frequency in s⁻¹ (per second). Multiplying them gives meters times per second, or m/s, which are the units of velocity. So the product directly yields a quantity describing how fast something travels, i.e., velocity. The other options have different units: mass is kilograms, acceleration is meters per second squared, and power is joules per second (watts); none match m/s.