Jay Ghosh

Asked: December 13, 2024In: Class 12 Physics

How much average power, over a complete cycle, does an a.c.source supply to a capacitor?

Zero, because current and voltage differ in phase by π/2 . Class 12 Physics Chapter 7 Alternating current Session 2024-2025.

Jay Ghosh

Asked: December 12, 2024In: Class 12 Physics

In a series LCR circuit, the voltage across an inductor, a capacitor and a resistor are 20 V, 20 V and 40 V, respectively, What is the phase difference between the applied voltage and the current in the circuit?

Zero, because V^l and Vc nulify each other and effectively the circuit is resistive in nature. Class 12 Physics Chapter 7 Alternating current Session 2024-2025.

Jay Ghosh

Asked: December 12, 2024In: Class 12 Physics

Difine capacitive reactance. write its SI units.

Capacitive reactance of a capacitor is the opposition offered by it for flow of a current through it. Capacitive reactance Xc = 1/Cw , where w is the angular frequency of current supply. SI unit of capacitive reactance is ohm ...

Jay Ghosh

Asked: December 12, 2024In: Class 12 Physics

Find the capacitance of the capacitor that would have a reactance of 100Ω when used with an a.c. source of frequency 5/π kHz.

Here Xc = 100Ω, v = 5/π kHz = 5000/π Hz ∴ C = 1/Xc . 2πv = 1/100 × 2π × 5000/π = 10-⁶F = 1µF. Class 12 Physics Chapter 7 Alternating current Session 2024-2025.

Jay Ghosh

Asked: December 12, 2024In: Class 12 Physics

A reactive element, in an a.c. circuit, causes the current flowing (i) to lag in phase by π/2 , (ii) to lead in phase by π/2 with respect to the applied voltage. Identify the element in each case.

(i) In an inductor current logs behaind the voltage by a phase angle of π/2 . (ii) In a capacitor current leads the voltage by a phase angle of π/2 . Class 12 Physics Chapter 7 Alternating current Session ...

Jay Ghosh

Asked: December 12, 2024In: Class 12 Physics

When a lamp is connected to an alternating voltage supply, it lights with the same brightness as when connected to a 12 V d.c. battery. what is the peak value of alternating voltage source?

The peak voltage of alternating voltage source Vm = 12 × √2 , V = 17 V. Class 12 Physics Chapter 7 Alternating current Session 2024-2025.

Jay Ghosh

Asked: December 12, 2024In: Class 12 Physics

An a.c. I = Im sin wt produces certain heat H in a resistor R over a time T = 2π/w . write the value of d.c. that would produce the same heat in the same resistor in the same time.

Equivalent value of d.c. = I effective = Im/√2 . Class 12 Physics Chapter 7 Alternating current Session 2024-2025.

Jay Ghosh

Asked: December 12, 2024In: Class 12 Physics

The electric mains in the house are marked 220 V, 50Hz. Write down the equuation for instantaneous voltage.

Equation for instantaneous voltage is V = 220 × √2 sin 2π (50)t = 311 sin 314t. Class 12 Physics Chapter 7 Alternating current Session 2024-2025.

Jay Ghosh

Asked: December 12, 2024In: Class 12 Physics

Difine the term ‘mutual inductance’ between the two coils.

Mutual inductance of two neighbouring coils is numerically equal to the amount of magnetic flux linked with one coil when unit current flows through the other coil. Class 12 Physics Chapter 6 Electromagnetic Induction Session 2024-2025.

Jay Ghosh

Asked: December 11, 2024In: Class 12 Physics

A solenoid is connected to a battery so that a steady current flows through it. if an iron core is inserted into the solenoid, will the current increase or decrease?

The current flowing through solenoid coil decrease. As the iron core is inserted into the solenoid, the magnetic field and consequently the magneti flux increases. in accordance with Lenz;s law the induced current resists the increase in magnetic flux. Hence, ...

Jay Ghosh

How much average power, over a complete cycle, does an a.c.source supply to a capacitor?

In a series LCR circuit, the voltage across an inductor, a capacitor and a resistor are 20 V, 20 V and 40 V, respectively, What is the phase difference between the applied voltage and the current in the circuit?

Difine capacitive reactance. write its SI units.

Find the capacitance of the capacitor that would have a reactance of 100Ω when used with an a.c. source of frequency 5/π kHz.

A reactive element, in an a.c. circuit, causes the current flowing (i) to lag in phase by π/2 , (ii) to lead in phase by π/2 with respect to the applied voltage. Identify the element in each case.

When a lamp is connected to an alternating voltage supply, it lights with the same brightness as when connected to a 12 V d.c. battery. what is the peak value of alternating voltage source?

An a.c. I = Im sin wt produces certain heat H in a resistor R over a time T = 2π/w . write the value of d.c. that would produce the same heat in the same resistor in the same time.

The electric mains in the house are marked 220 V, 50Hz. Write down the equuation for instantaneous voltage.

Difine the term ‘mutual inductance’ between the two coils.

A solenoid is connected to a battery so that a steady current flows through it. if an iron core is inserted into the solenoid, will the current increase or decrease?

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