امواج

The speed of a wave of frequency 100 Hz and wavelength 3.4 m is:

• 1 340 m/s
• 2 3.4 m/s
• 3 34 m/s
• 4 103.4 m/s

The beat frequency of two sources of 256 Hz and 260 Hz is:

• 1 2 Hz
• 2 4 Hz
• 3 258 Hz
• 4 516 Hz

In a stationary wave the points of zero amplitude are:

• 1 Wavefronts
• 2 Nodes
• 3 Crests
• 4 Antinodes

The Doppler effect is a change in the observed:

• 1 Mass
• 2 Amplitude only
• 3 Frequency due to relative motion
• 4 Speed of light

The fundamental frequency of a string of length L and wave speed v fixed at both ends is:

• 1 2 v / L
• 2 v / 2L
• 3 v / L
• 4 v L

The speed of a wave on a stretched string increases when the tension:

• 1 Increases
• 2 Is zero
• 3 Decreases
• 4 Is constant

Sound is a:

• 1 Transverse wave only
• 2 Electromagnetic wave
• 3 Surface wave only
• 4 Longitudinal wave

Constructive interference occurs when two waves meet:

• 1 In phase
• 2 At right angles
• 3 At different speeds
• 4 Out of phase by 180 degrees