Home 2nd Year Physics Notes Class 12 Physics Chapter 16 Notes – Alternating current

# Class 12 Physics Chapter 16 Notes – Alternating current

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In this post, I am sharing the Class 12 Physics Chapter 16 Notes PDF for the students of Intermediate Part 2. This chapter’s name is Alternating Current. Students can download the Class 12 Physics Chapter 16 Notes PDF on their laptops or mobile. These Physics Notes are for all the boards working under the Punjab Board like Gujranwala Board, Lahore Board, Faisalabad Board, Multan Board, Rawalpindi Board, Sargodha Board, DG Kahn Board, and Sahiwal Board. Here are the complete FSC 2nd Year Physics Notes PDF chapters.

## FSC Part 2 Physics Chapter 16 Notes – Alternating Current

Class 12 Physics Notes

#### Alternating Current

Alternating current (A.C) is that which is produced by a voltage source whose polarity keeps on reversing with time. Here the terminal A of the source is positive with respect to terminal B and it remains so during a time interval O to T/2. At T/2 the terminals change their polarity such that A becomes negative and B positve during time T/22 – T. As a resuldt of this change of polarity the direction of current flow in the circuit also changes.

#### Define Choke?

Choke

It is a coil that consists of thick copper wire wound closely in a large number of turns over soft iron laminated cores. This makes the inductance L of the coil quite large whereas its resistance R is very small. Thus it consumes extremely little power. It is used in A.C. circuits to limit current with extremely small wastage of energy as compared to a resistance or a rheostat.

#### Principal of Metal Detector?

A coil and capacitor are electrical components that together can produce oscillations of current. An L-C circuit behaves just like an oscillating mass-spring system. In this case, energy oscillates between a capacitor and an inductor. The circuit is called an electrical oscillator. As such oscillators A and B are used in the operation of a common type of metal detector in the absence of any nearby metal object, the inductances LA and LB are the same and hence the resonance frequency of the two circuits is also the same.