Wave Calculations and Transverse Waves

Wave Calculations

Determining Number of Waves from Crests

• If a wave starts and ends with a crest, the number of full waves is one less than the number of crests.

• Example: 10 crests equals 9 full waves.

Calculating Frequency

• Frequency can be calculated using the number of wavelengths over time: frequency =
  ewline number
  ewline of
  ewline wavelengths / time

• Alternatively, calculate the speed first and then find the frequency.

• Given: 10 crests pass in 3 seconds, and the wavelength is 20 meters.

• Number of full waves: 9

• Frequency = 9 / 3 = 3 Hz

Calculating Velocity

• Velocity is the frequency times the wavelength: v = f \lambda

• Convert wavelength to meters: 20 cm = 0.2 meters (since 1 cm = 0.01 m).

• v = 3 \times 0.2 = 0.6 m/s

Multiple Choice Strategy

• Eliminate options to increase the probability of selecting the correct answer.

• Carefully check units and conversions to avoid careless mistakes.

Transverse Waves

Definition

• Transverse Wave: A wave where particles move perpendicular to the direction of propagation.

• Key aspects to include in the definition:

  • Motion of particles.

  • Perpendicular direction to wave propagation. Propagation is the movement of or oscillation of the wave. Instead of propagation, oscillation or movement of the wave can be used.

Diagram

• To illustrate two wavelengths, draw two full waves.

• Label each full wave.

Frequency Calculation

• Given: Wavelength (\lambda) = 0.4 meters, Velocity (v) = 0.25 meters per second, and Amplitude (A) = 0.3 meters.

• Amplitude is extra information and should be ignored when calculating frequency, wavelength, or speed unless specifically calculating amplitude.

• Formula: v = f \lambda

• Rearrange to solve for frequency: f = v / \lambda

• f = 0.25 / 0.4