Alternating Current Physics - Alternating Current

Sunita and her friends went to an exhibition. The guard standing there asked them to pass through a metal detector. Sunita's friends were first afraid but when Sunita told them the reason and explain its working.
Answer the following questions :
(a) State the principle on which metal detector works.
(b) If a person passing through metal detector has some metallic object then why does it produces sound?
(c) Tell two qualities of Sunita which she showed while explaining the reason for passing through it.

Explain the root mean square value of alternating current.

When a capacitor is joined with a series LR circuit in series, then current flowing through the circuit increases. Explain, why?

Power factor of a coil in an ac circuit at 60 hertz frequency is 0.707 . If frequency of ac source becomes 120 hertz, then what will be power factor?

What is the principle on which a transformer works? Can it be used in de circuit?

Power factor of an ac circuit is 0.5. What is the phase difference between current and voltage in the circuit?

What is power factor? Explain.

Alternating current cannot be measured by de ammeter because:

Frequency and potential difference of AC sent to homes in India is:

Peak value of applied alternating voltage in a LR cir- cuit is 5 V. If magnitude of maximum voltage across the ends of resistor is 3 V. then maximum value of voltage across the inductor is

The number of turns in primary and secondary coils of a transformer are 100 and 300 respectively. If in- put power is 60 W, then output power will be:

Draw a phasor diagram for series LCR circuit joined with ac voltage source and obtain an expression for impedance of the circuit.