Periodic Waves - AP Physics 2

1. What is the unit of wave speed?

   Meters per second (m/s). Standard SI unit for velocity measurements.

2. What is the formula for the period of a wave?

   $T = \frac{1}{f}$. Period is the reciprocal of frequency.

3. State the formula for the frequency of a wave.

   $f = \frac{1}{T}$. Frequency is the reciprocal of period.

4. What is the amplitude of a wave?

   The maximum displacement from the equilibrium position. Amplitude measures the strength of oscillation.

5. Calculate wavelength if wave speed is 20 m/s and frequency is 4 Hz.

   $\nu = 5$ m. Using $\lambda = \frac{v}{f} = \frac{20}{4} = 5$ m.

6. What is the principle of superposition?

   Waves add their amplitudes when they overlap. Fundamental principle of wave interference.

7. What is the result of destructive interference?

   Waves cancel each other out, reducing amplitude. Occurs when waves are out of phase.

8. What happens to frequency if the wavelength is doubled?

   Frequency is halved, assuming constant speed. From $v = f\lambda$, if $\lambda$ doubles and $v$ constant, $f$ halves.

9. Define constructive interference.

   When two waves meet and their amplitudes add up. Waves combine to create larger amplitude.

10. State the unit of amplitude.

    Meters (m). Amplitude is a distance measurement.

11. What is the relationship between period and frequency?

    They are reciprocals: $T = \frac{1}{f}$. Frequency and period are inverse quantities.

12. Define a longitudinal wave.

    Wave with oscillations parallel to wave direction. Particle motion is along the direction of wave travel.

13. What is the definition of a wavelength?

    The distance between consecutive crests or troughs. One complete cycle of the wave pattern.

14. Calculate the frequency given a period of 0.5 seconds.

    $f = 2$ Hz. Using $f = \frac{1}{T} = \frac{1}{0.5} = 2$ Hz.

15. Find the frequency of a wave with period 0.25 seconds.

    $f = 4$ Hz. Using $f = \frac{1}{T} = \frac{1}{0.25} = 4$ Hz.

16. What is the formula for the power of a wave?

    $P = I \times A$. Power equals intensity times area.

17. What is the unit of frequency?

    Hertz (Hz). Named after Heinrich Hertz, represents cycles per second.

18. Find the speed of a wave with frequency 3 Hz and wavelength 2 m.

    $v = 6$ m/s. Using $v = f \times \lambda = 3 \times 2 = 6$ m/s.

19. What is an antinode?

    A point of maximum amplitude in a standing wave. Location of constructive interference in standing waves.

20. What is the phase difference in constructive interference?

    Multiples of $2\text{π}$ radians. Waves are in phase for maximum reinforcement.

21. What is the formula for intensity of a wave?

    $I = \frac{P}{A}$. Intensity is power per unit area.

22. Define node in a standing wave.

    A point of zero amplitude. Location of destructive interference in standing waves.

23. State the relationship between intensity and amplitude.

    Intensity is proportional to amplitude squared. Energy carried by wave depends on amplitude squared.

24. State the unit of wavelength.

    Meters (m). Standard SI unit for distance measurements.

25. What is the phase difference in destructive interference?

    Odd multiples of $\text{π}$ radians. Waves are out of phase for cancellation.

26. What is a transverse wave?

    Wave with oscillations perpendicular to wave direction. Particle motion is at right angles to wave propagation.

27. Define wavefront.

    A surface over which an oscillation has a constant phase. Represents points of equal phase in wave propagation.

28. What is the speed of sound in air at room temperature?

    Approximately 343 m/s. Standard reference value for sound wave calculations.

29. Calculate the wave speed if wavelength is 4 m and period is 0.5 s.

    $v = 8$ m/s. Using $v = \frac{\lambda}{T} = \frac{4}{0.5} = 8$ m/s.

30. Determine the speed of a wave with wavelength 3 m and frequency 5 Hz.

    $v = 15$ m/s. Using $v = f \times \lambda = 5 \times 3 = 15$ m/s.

31. Find the wavelength if speed is 10 m/s and frequency is 2 Hz.

    $\nu = 5$ m. Using $\lambda = \frac{v}{f} = \frac{10}{2} = 5$ m.

32. Determine the period if the frequency is 5 Hz.

    $T = 0.2$ s. Using $T = \frac{1}{f} = \frac{1}{5} = 0.2$ s.

33. Find the period if frequency is 0.25 Hz.

    $T = 4$ s. Using $T = \frac{1}{f} = \frac{1}{0.25} = 4$ s.

34. Define frequency in terms of wave cycles.

    Number of cycles per second. Measures how often the wave pattern repeats.

35. What is the Doppler effect?

    Change in frequency due to relative motion of source and observer. Apparent frequency shift due to motion.

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