Physics MCQs

Physics

Waves


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#57

The frequency of a sound wave is 1000 Hz. The wavelength in water (speed = 1500 m/s) is

A) 0.15 m

B) 0.3 m

C) 1.5 m

D) 3.0 m

Answer:   B
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#58

The frequency of a sound wave is 500 Hz. The wavelength in steel (speed = 5000 m/s) is

A) 0.1 m

B) 1 m

C) 10 m

D) 100 m

Answer:   A
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#59

The intensity of a sound wave is 10\(^{-6}\) W/m\(^2\). The sound level in decibels is

A) 60 dB

B) 70 dB

C) 80 dB

D) 90 dB

Answer:   C
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#60

The intensity of a sound wave is 10\(^{-3}\) W/m\(^2\). The sound level in decibels is

A) 90 dB

B) 100 dB

C) 110 dB

D) 120 dB

Answer:   B
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#61

The sound level of a sound is 50 dB. Its intensity is

A) 10\(^{-7}\) W/m\(^2\)

B) 10\(^{-8}\) W/m\(^2\)

C) 10\(^{-9}\) W/m\(^2\)

D) 10\(^{-10}\) W/m\(^2\)

Answer:   A
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#62

The sound level of a sound is 120 dB. Its intensity is

A) 10\(^{-6}\) W/m\(^2\)

B) 10\(^{-4}\) W/m\(^2\)

C) 10\(^{-2}\) W/m\(^2\)

D) 1 W/m\(^2\)

Answer:   C
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#63

The phenomenon of beats is due to

A) Reflection

B) Refraction

C) Interference

D) Diffraction

Answer:   C
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#64

The beat frequency is equal to

A) Sum of the frequencies

B) Difference of the frequencies

C) Product of the frequencies

D) Ratio of the frequencies

Answer:   B
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