What direct current will produce the same amount of thermal energy, in a particular resistor, as an alternating current that has a maximum value of 2.60 A?
The value of the direct current is 1.84 A.
Average power dissipated in resistance R when the current is AC and DC should be equated to find the direct current which will produce the same amount of thermal energy as an alternating current of 2.60 A
Average power dissipated in resistance R when current is AC.
The power is dissipated in resistor R when current is DC.
Both these powers produce the same thermal energy. Hence,
Substitute 2.60A for i in the above equation.
Hence, the value of the direct current is 1.84A.
An ac generator provides emf to a resistive load in a remote factory over a two-cable transmission line. At the factory a stepdown transformer reduces the voltage from its (rms) transmission value to a much lower value that is safe and convenient for use in the factory. The transmission line resistance is , and the power of the generator is . If , what are (a) the voltage decreases V along the transmission line and (b) the rate at which energy is dissipated in the line as thermal energy? If , what are (c) V and (d) ? If , what are (e) V and (f) ?
In a certain series RLC circuit being driven at a frequency of , the maximum voltage across the inductor is times the maximum voltage across the resistor and times the maximum voltage across the capacitor. (a) By what angle does the current lag the generator emf? (b) If the maximum generator emf is , what should be the resistance of the circuit to obtain a maximum current of ?
In an oscillating LC circuit in which , the maximum potential difference across the capacitor during the oscillations is and the maximum current through the inductor is . (a)What is the inductance L? (b)What is the frequency of the oscillations? (c) How much time is required for the charge on the capacitor to rise from zero to its maximum value?
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