HARD
12th Karnataka Board
IMPORTANT
Earn 100

Show that the total energy of LC oscillations is conserved.

Important Questions on Alternating Current

MEDIUM
12th Karnataka Board
IMPORTANT
Physics Crash Course (Based on Revised Syllabus-2023)>Chapter 7 - Alternating Current>Exercise>Q 34
In a series L-C circuit, the voltages across L and C are 180° out of phase; while in a parallel L-C circuit, the current in L and C are out of phase. Explain.
HARD
12th Karnataka Board
IMPORTANT
Physics Crash Course (Based on Revised Syllabus-2023)>Chapter 7 - Alternating Current>Exercise>Q 35
A charged capacitor is connected across an inductor with a wire having practically no resistance. Show that the discharge of the capacitor is oscillatory. Find the frequency of oscillations.
MEDIUM
12th Karnataka Board
IMPORTANT
Physics Crash Course (Based on Revised Syllabus-2023)>Chapter 7 - Alternating Current>Exercise>Q 36
A circuit containing a 20Ω resistor and 0.1μF capacitor in series is connected to 230V a.c. supply of angular frequency 100rad s-1. What is the impedance of the circuit?
HARD
12th Karnataka Board
IMPORTANT
Physics Crash Course (Based on Revised Syllabus-2023)>Chapter 7 - Alternating Current>Exercise>Q 37
A 20W, 50V, filament is connected in series to an a.c. mains of 250V, 50Hz. Calculate the value of the capacitor required to run the lamp.
EASY
12th Karnataka Board
IMPORTANT
Physics Crash Course (Based on Revised Syllabus-2023)>Chapter 7 - Alternating Current>Exercise>Q 38
Calculate the impedance of a coil of resistance 3Ω and reactance 4Ω.
HARD
12th Karnataka Board
IMPORTANT
Physics Crash Course (Based on Revised Syllabus-2023)>Chapter 7 - Alternating Current>Exercise>Q 39
An arc takes a current of 10A at 80V. Find the inductance, which should be put in series to work the arc from 220V, 50Hz supply.
MEDIUM
12th Karnataka Board
IMPORTANT
Physics Crash Course (Based on Revised Syllabus-2023)>Chapter 7 - Alternating Current>Exercise>Q 40

The virtual current in the a.c. circuit shown in Figure, is 1.0A. Find (i) virtual voltage across the coil L (ii) impedance of the circuit and (iii) reactance of the coil.

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EASY
12th Karnataka Board
IMPORTANT
Physics Crash Course (Based on Revised Syllabus-2023)>Chapter 7 - Alternating Current>Exercise>Q 41
What is the phase relation between current and voltage in (i) a resistor,?