IB Physics Glossary
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absolute, is proportional to the average kinetic energy of the molecules of a substance. (d)
The photoelectric effect
is the quantity of thermal energy required to raise the temperature of an object by one degree. (d)
Threshold hearing curve
shows that the sound intensity required to be heard is quite different for different frequencies. Most sensitive frequencies (≈ 3kHz) have lower dB values - less sound intensity is required to for the sound to be heard. Least sensitive frequencies have higher dB values - more sound intensity is required for the sound to be heard. Negative dB values indicate sound intensity is below I0, the threshold intensity of hearing. The graph below shows how the curve varies with age: 20, 40 and 60 years.
Threshold intensity of hearing
is the minimum intensity at which sound is heard, I0 = 1 x 10−12 Wm−2.
is the sensation of ringing in the ears which can be caused by short-term exposure to loud sounds.