If the ultrasound instrument's output is increased by 60 dB, the beam intensity increases by approximately how many times?

• A. one million times
• B. five percent
• C. two times
• D. twenty times

Answer: (A)

Decibels express a log-scale relationship for intensity. The ratio of final to initial intensity is I2/I1 = 10^(ΔdB/10). With a 60 dB increase, that becomes 10^(60/10) = 10^6, which is one million. So the beam intensity is amplified by a factor of one million. The other options describe much smaller changes (for example, doubling is about a 3 dB increase, and twenty times is around 13 dB), so they don’t match a 60 dB boost.