NCTI Installer Technician Practice Test

The term that refers to the logarithmic measure of the ratio of two power levels is "Decibel." A decibel is a specific unit of measurement utilized to express how much one value differs from another on a logarithmic scale. This is particularly important in fields like telecommunications and audio engineering, where understanding power levels and signal strengths is critical.

The decibel format allows for easier manipulation of large numbers, as it compresses the scale, making it more manageable. Specifically, a decibel is ten times the logarithm (base 10) of the ratio of two power levels, which is why it is widely adopted for comparing sound intensity, electrical power, and signal strength.

Bel, while related, is a broader unit that represents a larger ratio and is less commonly used in practice. Ratio and fraction do not specify a logarithmic relationship, limiting their applicability to this specific context of measuring power levels. Thus, "Decibel" is the appropriate term in this scenario.