Which parameter change decreases the repetition rate?

• A. Increasing repetition rate (Hz)
• B. Decreasing repetition rate (Hz)
• C. Increasing pulse width (ms)
• D. Increasing wavelength (nm)

Answer: (B)

Repetition rate is the number of laser pulses delivered per second, measured in hertz. To decrease the repetition rate you would lower this frequency value, meaning fewer pulses occur each second. Among the options, decreasing the repetition rate directly reduces how often pulses are emitted, which is exactly what the question asks for. Increasing the repetition rate would do the opposite. Increasing pulse width changes how long each individual pulse lasts, not how often pulses are fired. Increasing wavelength changes what tissue is targeted, not the timing of pulses. So the change that lowers how often pulses come out is decreasing the repetition rate.