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All 10 questions. After you submit, each question shows the right answer and why. Back to the quick check
Which of these waves can travel through the empty space between the Sun and Earth?
When a wave passes a floating leaf on a pond, the wave carries the leaf all the way across the pond.
Sound travels faster through water than through air.
In a sound wave travelling through air, which way do the air molecules move?
A wave has a frequency of 5 Hz and a wavelength of 2 m. What is its speed in m/s?
Two identical sound waves of amplitude 1 unit arrive at the same point exactly half a cycle (π radians) out of phase. What is the resulting amplitude?
A 440 Hz tone travels through air at 20 °C, where sound moves at 343 m/s. What is its wavelength in metres, to two decimal places?
Two waves of equal amplitude A = 1 and the same frequency differ in phase by φ = π/2 radians. What is the amplitude of their sum, to two decimal places?
A string 0.50 m long is fixed at both ends. What is the wavelength, in metres, of its third standing-wave mode (n = 3), to two decimal places?
The superposition principle is exact for solutions of the linear wave equation. Explain what assumption about amplitude makes real mechanical waves linear, and what changes when it fails.
