Sound Waves (physics Only) (ht Only) (GCSE Physics)

A sound wave in air has frequency 500 Hz and intensity I0. If the amplitude of pressure oscillation is doubled, what is the new intensity in terms of I0? (Intensity ? amplitude^2.)

A student measures the minimum audible level at a frequency and finds 20 arbitrary units for a young person and 60 units for an older person. Which physical effect could explain the older person’s raised threshold at high frequencies?

A plane wave in air of wavelength 0.34 m strikes a rigid wall. Which two statements are correct about the reflected wave?

An ultrasound pulse (1 MHz) is emitted into tissue where speed is 1540 m/s. What is the pulse wavelength in tissue?

A moving-coil microphone diagram shows a coil attached to a diaphragm inside a magnetic field. What electrical quantity is produced directly when the diaphragm vibrates?

A tube closed at one end has its first resonance (fundamental) at 170 Hz. If the speed of sound is 340 m/s, what is the length of the tube? (For closed–open tube fundamental ? = 4L.)

A sound source radiates 0.5 W of acoustic power uniformly. What intensity is at a distance of 2 m? I = P / (4pr^2).

A moving listener hears frequency f` from a stationary source frequency f due to the Doppler effect. If the listener moves toward the source at speed v_l (<< speed of sound c), which approximate relation applies?

A speaker’s cone vibrates with maximum displacement amplitude A. For small sinusoidal motion, which property of the sound wave is directly proportional to A?

A tube open at both ends supports a standing sound wave whose fundamental frequency is 256 Hz. If the speed of sound is 340 m/s, what is the length of the tube? (For an open–open tube the fundamental has ? = 2L.)

A sound wave has pressure amplitude p0 and intensity I ? p0^2. If the intensity at 1 m is 0.02 W/m^2, what intensity at 2 m from a point source (neglecting absorption)?