A 50-m coil carries a current of 2 amperes. The energy stored in a magnetic field is:
Correct answer: B. 0.1 joule
- A. 10 joule
- B. 0.1 joule
- C. 0.01 joule
- D. 1.0 joule
Explanation
Using the formula for energy stored in magnetic field of a coil (E = ½ × L × I²)E = ½ × L × I² E = ½ × (50 × 10-3) × (2)² = 0.1 J
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About AC Through Resistor, Capacitor and Inductor
Alternating current through a resistor, capacitor and inductor involves phase relationships between voltage and current, reactance, impedance and energy transfer. A resistor keeps voltage and current in phase, while a capacitor and inductor produce opposite phase shifts, a distinction used in circuit diagrams and numerical calculations.
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