Phase difference

The diagram shows two sinusoidal waveforms.

At time t = 0 the waves are in phase. At the dotted line, t = 18 s.

At which time is the phase difference between the two oscillations ⅛ of a cycle?

• 8.0s

• 4.5s

• 4.0s

• 9.0s

A signal has a frequency of 2.0 MHz.What is the period of the signal?

• 5μs

• 200ns

• 500ns

• 2μs

A displacement-time graph for a transverse wave is shown in the diagram.

The phase difference between X and Y can be expressed as nπ.

What is the value of n?

• 3.0

• 1.5

• 2.5

• 6.0

The frequency of a certain wave is 500 Hz and its speed is 340 ms^–1.What is the phase difference between the motions of two points on the wave 0.17 m apart?

• π rad

• π/4 rad

• π/2 rad

• 3π/4 rad

Noise reduction headphones actively produce their own sound waves in order to cancel out external sound waves.

A microphone in the headphones receives waves of one frequency. A loudspeaker in the headphones then produces a wave of that frequency but of a different phase.

What is the phase difference between the external sound wave and the wave produced by the loudspeaker in the headphones?

• 360°

• 180°

• 90°

• 270°

What is the phase difference between two points 30cm apart if the wavelength is 1.5m?

• 1.26 rad

• 126 rad

• 1.25663 rad

• 31 rad

What is the phase difference between points O and D?

• zero

• 2π

• π

• π/2

If the path difference between B and C is 8nm, what is the wavelength?

A wave is displaced forward by +6 radians from O. Select which two points are closest to it

• F

• B

• C

• D

• E

Describe the difference between longitudinal and transverse waves.