A student is taking a 3-question quiz where each question is a true/false choice. The student guesses randomly on all questions. The probability of guessing exactly one question correctly is calculated using the expression: $3 \times (0.5)^1 \times (0.5)^2$. Explain what each of the three components of this expression (the '3', the '$(0.5)^1$', and the '$(0.5)^2$') represents in the context of this specific scenario.