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V=V₀ (e⁻ᵗ/ᴿᶜ)

The above equation will yield that the intercept (b) is lnV₀. Linest will tell you about the uncertainty in b but not V₀ . Determine the uncertainty in V₀ . Hint: σb= √(db/dV₀ )² σ ²V₀




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Final answer:

The uncertainty in the initial voltage, V₀, can be calculated by using the uncertainty in the y-intercept from linear regression, applying the differentiation of the natural logarithm, and hence finding the propagation of uncertainty. This is done by the formula σ₀ = V₀ * σb, with σb representing the known uncertainty of the y-intercept.

Step-by-step explanation:

The student is dealing with an equation related to the exponential decay in an electrical circuit or a similar physical process, represented in the form V=V₀ (e-t/RC), where V₀ is the initial voltage, V is the voltage at time t, R is the resistance, and C is the capacitance. To find the uncertainty in V₀, we need to consider the linear regression analysis and the uncertainty in the y-intercept (b), which is represented by ln(V₀). Note that the relationship σb = √(db/dV₀ )² σV₀² suggests we can calculate the uncertainty in V₀ by differentiating b (which is ln(V₀)) with respect to V₀ and then plugging in the known uncertainty value for the y-intercept (σb) from the least-squares regression analysis.

The differentiation will yield db/dV₀ = 1/V₀. Therefore, the uncertainty in V₀, or σV₀, can be calculated by rearranging the equation to σV₀ = V₀ * σb, where the value of σb is provided by the regression analysis. This demonstrates the propagation of uncertainty from the linear fit to the original variable of interest.

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