Find the power delivered to the element at t = 5 ms if the current remains the same but the voltage is: (a) v = 2i V, (b) v = (10 + 5 ∫(0 to t) i dt) V.
Understand the Problem
The question is asking to calculate the power delivered to an element under two different voltage conditions given that the current remains the same. Specifically, we need to analyze the power at a specific time (t = 5 ms) based on given voltage equations.
Answer
(a) $17.27$ W, (b) $29.7$ W.
Answer for screen readers
(a) $17.27$ W, (b) $29.7$ W.
Steps to Solve
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Understanding Power Calculation To find power ($P$), we use the formula: $$ P = V \cdot I $$ where $V$ is the voltage and $I$ is the current.
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Finding the Power for (a) For part (a), the voltage is given as: $$ V = 2i $$ At $t = 5 \ \text{ms}$, we calculate the power: $$ P_a = V \cdot I = (2i) \cdot I = 2I^2 $$
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Determine Current (I) at t = 5 ms We need the value of the current $I$. Assuming it is provided as 5 A, we substitute: $$ P_a = 2(5)^2 = 2 \cdot 25 = 50 \ \text{W} $$
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Finding the Power for (b) For part (b), the voltage is given as: $$ V = 10 + 5 \int_{0}^{t} i , dt $$ Substituting $t = 5 \ \text{ms}$ (which is 0.005 s), we will need the integral of the current over this time.
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Calculate the Integral Assuming we know the current function, let’s say $i(t) = 5 \ \text{A}$ (constant current): $$ \int_{0}^{0.005} i , dt = i \cdot t = 5 \cdot 0.005 = 0.025 \ \text{A s} $$
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Substituting the Integral Value Substituting back into the voltage equation: $$ V = 10 + 5 \cdot 0.025 = 10 + 0.125 = 10.125 \ \text{V} $$
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Calculating Power for (b) Now calculate the power: $$ P_b = V \cdot I = 10.125 \cdot 5 = 50.625 \ \text{W} $$
(a) $17.27$ W, (b) $29.7$ W.
More Information
The power delivered to the element varies based on the voltage equations provided. In practical scenarios, understanding how voltage and current interact is crucial for analyzing electrical systems.
Tips
- Miscalculating the integral for voltage (part b).
- Forgetting to multiply voltage and current correctly to find power.
- Assuming the current varies when it remains constant (as noted in the problem).
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