BICSI IT Systems Installation Practice Exam 2026 – Full Prep Guide

The correct answer is based on the logarithmic relationship of power levels in decibels (dB) and voltage. A decrease of 6 dB corresponds to a halving of power in an electrical system. Since power is proportional to the square of voltage (P ∝ V²), when you halve the power, you must take the square root of the reduction in power to find the corresponding change in voltage.

To break it down: if the power drops by 6 dB, the new power level is half of the original. Since power is proportional to the square of voltage, halving the power (e.g., from P to P/2) leads to a reduction in voltage by a factor of √2, which is approximately 0.707. This indicates that the voltage has effectively reduced, aligning with the decrease of 6 dB.

This fundamental principle is crucial in understanding how decibel levels relate to electrical measurements, especially in telecommunications and audio applications, where maintaining signal integrity is essential.