Where does an inductor store energy?
Correct answer A. In its magnetic field
Topic / 897 questions
Physics MCQs
Page 28 of Physics multiple-choice questions with answers. Tap an option to check yourself.
Page 28 of 45
Two identical coaxial circular loops carry equal currents in the same direction. What happens to the currents as the loops move towards each other?
Correct answer D. Each decreases
In a series LCR circuit with applied RMS voltage V and RMS voltages V_R, V_L and V_C across R, L and C, which relation holds?
Correct answer A. V² = V_R² + (V_L − V_C)²
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In an a.c. circuit containing only resistance, what is the phase angle between voltage and current?
Correct answer C. Zero
In an AC circuit, for which values of voltage and current does Ohm’s law hold?
Correct answer D. All of the above
A coil has a resistance of 100 Ω. With a 1000 Hz AC supply, the applied voltage leads the current by 45°. What is the inductance of the coil?
Correct answer A. 16 mH
An a.c. series circuit has a resistance of 4 Ω and an inductive reactance of 3 Ω. What is its impedance?
Correct answer D. 5 Ω
What is the power factor of a series L-C-R circuit at resonance?
Correct answer C. 1
In which kind of circuit is a choke used to limit current?
Correct answer B. AC circuits
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A 10 Ω electric heater is connected to a 220 V, 50 Hz mains supply. What is the peak potential difference across the heater element?
Correct answer B. 220√2 V
For a circuit made up of a capacitance C and a resistance R, which expression gives its frequency?
Correct answer D. 1/RC
A coil develops an induced emf of 2 V when the current through it changes at 4 A s⁻¹. What is its self-inductance?
Correct answer C. 0.5 H
A pure inductor L and a pure capacitor C are connected in parallel across a sinusoidal potential difference V. How do the potential differences across L and C compare?
Correct answer D. They are the same
What does an ammeter connected in an AC circuit measure?
Correct answer B. RMS value of the current
A wire of resistance R is wound into a coil of inductance L. What is the impedance of the coil at frequency f?
Correct answer D. √(R² + 4π²f²L²)
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A capacitor is connected in series with a lit bulb on an a.c. supply. What happens to the bulb’s brightness if a glass plate is inserted between the capacitor plates?
Correct answer A. It increases
A 100 µF capacitor is connected in series with a 12 V, 50 Hz source. Roughly what is its capacitive reactance?
Correct answer C. 32Ω
In a purely capacitive circuit, how is the current related to the voltage?
Correct answer C. It leads the voltage by π/2
When an alternating current passes through a capacitor, how are current and voltage related in phase?
Correct answer C. The current leads the voltage by 90°
In a purely resistive AC circuit, how are the voltage and current related?
Correct answer A. They have zero phase difference