Anonymous

Register for more FREE stuff!

my subscriptions

Standing Waves and Resonance

Question 1

Which of these is a requirement for a standing wave to form?

  • A) Two identical waves moving in the same direction.
  • B) Two identical waves moving in the opposite direction.
  • C) Two waves with identical wavelengths but different frequencies.
  • D) One end of the wave must be free.

Answers and Explanations

Question 2

What is referred to as a node of a standing wave?

  • A) The point on the wave that always oscillates between the 2 extremes.
  • B) The point on the wave that never moves.
  • C) Points that are separated by a distance of \(\frac{\lambda}{4}\)
  • D) A standing wave doesn't have nodes.

Answers and Explanations

Question 3

Which of these is true for a standing wave?

  • A) There is no progression of energy.
  • B) All points between 2 successive nodes are out of phase.
  • C) All points have the same amplitude.
  • D) All particles have the same frequency.

Answers and Explanations

Question 4

What is critical damping?

  • A) When an object tends to the equilibrium position slowly.
  • B) When an object returns to equilibrium quickly, but without crossing the equilibrium point.
  • C) All damping is critical.
  • D) When an object returns to equilibrium after 2-3 oscillations.

Answers and Explanations

Question 5

What is resonance?

  • A) When the driving frequency is equal to the reciprocal natural frequency we get the largest amplitude.
  • B) When the driving frequency is equal to the reciprocal natural frequency we get the smallest amplitude.
  • C) When the driving frequency is equal to the natural frequency we get the smallest amplitude.
  • D) When the driving frequency is equal to the natural frequency we get the largest amplitude.

Answers and Explanations

Question 6

In what way does damping affect resonance?

  • A) It reduces the maximum amplitude.
  • B) It reduces the resonant frequency.
  • C) It reduces both the maximum amplitude and the resonant frequency.
  • D) It increases the resonant frequency.

Answers and Explanations

Question 7

Which of the following statements about standing waves is correct?

  • A) All points on a standing wave have the same amplitude.
  • B) Standing waves are formed by the superposition of two waves traveling in opposite directions.
  • C) Standing waves transfer energy from one point to another.
  • D) All points on a standing wave are in phase.

Answers and Explanations

Question 8

For a standing wave on a string fixed at both ends, the distance between two adjacent nodes is \(0.5 \, \mathrm{m}\). What is the wavelength of the wave?

  • A) \( 0.5 \, \text{m} \)
  • B) \( 1.0 \, \text{m} \)
  • C) \( 1.5 \, \text{m} \)
  • D) \( 2.0 \, \text{m} \)

Answers and Explanations

Question 9

In a standing wave, what is the phase difference between two points that are one-quarter of a wavelength apart?

  • A) \(0^\circ\)
  • B) \(90^\circ\)
  • C) \(180^\circ\)
  • D) \(270^\circ\)

Answers and Explanations

Question 10

A pipe closed at one end has a length of \(0.85 \, \mathrm{m}\). If the speed of sound in air is \(340 \, \mathrm{m/s}\), what is the fundamental frequency of the standing wave in the pipe?

  • A) \(100 \, \text{Hz}\)
  • B) \(200 \, \text{Hz}\)
  • C) \(300 \, \text{Hz}\)
  • D) \(400 \, \text{Hz}\)

Answers and Explanations

Question 11

What happens to the amplitude of oscillation of a system at resonance when the driving frequency matches the natural frequency?

  • A) The amplitude is zero.
  • B) The amplitude remains constant.
  • C) The amplitude is maximum.
  • D) The amplitude increases indefinitely.

Answers and Explanations

Question 12

How does increasing the damping of a system affect the resonance curve?

  • A) The amplitude at resonance increases, and the resonant frequency shifts higher.
  • B) The amplitude at resonance decreases, and the resonant frequency shifts lower.
  • C) The amplitude at resonance decreases, but the resonant frequency remains the same.
  • D) The amplitude at resonance increases, but the resonant frequency remains the same.

Answers and Explanations

Question 13

A mass-spring system has a natural frequency of \(5.0 \, \mathrm{Hz}\). If an external driver oscillates at \(5.0 \, \mathrm{Hz}\), what is the amplitude of oscillation of the mass compared to when the driver frequency is \(4.5 \, \mathrm{Hz}\), assuming minimal damping?

  • A) The amplitude is the same at both frequencies.
  • B) The amplitude is greater when the driver frequency is \(5.0 \, \mathrm{Hz}\).
  • C) The amplitude is greater when the driver frequency is \(4.5 \, \mathrm{Hz}\)
  • D) There is no oscillation at \(4.5 \, \mathrm{Hz}\).

Answers and Explanations

Question 14

A string fixed at both ends has a length of \(1.2 \, \mathrm{m}\). The speed of waves on the string is \(240 \, \mathrm{m/s}\). What is the frequency of the second harmonic?

  • A) \( 100 \, \text{Hz} \)
  • B) \( 200 \, \text{Hz} \)
  • C) \( 300 \, \text{Hz} \)
  • D) \( 400 \, \text{Hz} \)

Answers and Explanations