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# Physics Practical Class 12 - To convert the given galvanometer (of known resistance and figure of merit) into an ammeter of desired range and to verify the same. Viva Questions with Answers

1) What is an Ammeter?

The magnitude of current flowing in a circuit can be determined by a device which is known as an ammeter. An ammeter measures both direct current and alternate current, and also it works with or without the presence of the magnetic field.

2) What is a Galvanometer?

To detect the direction and strength of a small current present in a circuit, a device is used, which is known as a galvanometer. A galvanometer only measures the direct current, and it works in the presence of the magnetic field.

3) How can a galvanometer be used as an ammeter?

A large current can be detected by converting a galvanometer into an ammeter. Since a galvanometer is a device used to detect or measure small currents, to alter a galvanometer into an ammeter, a shunt resistance is connected parallel to the galvanometer where the shunt resistance is a resistance of low value.

4) What is shunt resistance?

Shunt resistance is a resistance of low value. A shunt resistor is made using a material of low-temperature coefficient resistance value. It can be used for measuring the range to which it is extended when it is connected in parallel with an ammeter. And the current through the load can be determined when the same shunt resistance is connected in series with the load. For converting a galvanometer into an ammeter, shunt resistance is used.

5) What is the reduction factor?

In order to produce 45âˆ˜ deflection in a galvanometer, a current is required, which is known as a reduction factor; it is used in a tangent galvanometer. The reduction factor is measured in ampere and denoted by K.

6) Why is an ammeter always connected in series?

Since the internal resistance of an ammeter is low, it is always connected in series. There are high chances of short-circuiting if the ammeter is connected in parallel.

7) How does current electricity differ from static electricity?

As the name suggests, static electricity is static, whereas current electricity is dynamic. The form of electricity in which charges constantly flow is known as current electricity.

8) What is Static Electricity?

Fundamentally, the phenomenon of static electricity rises when the positive and negative charges are divided. Electric charges that build up on the surface of materials or substances are known as static electricity. These electric charges remain static until they are discharged or grounded. This type of electricity is formed due to friction.

9) What is a Voltmeter?

The potential difference or voltage among two points of an electronic or electrical circuit is measured using an instrument which is known as a voltage metre or voltmeter.

10) What is the working principle of a voltmeter?

A voltmeter is that it must be connected in parallel to the circuit in which the voltage has to be measured; this is the basic principle of a voltmeter. A voltmeter is built in such a way that it has a very high resistance value, and this is the reason why a parallel connection is used.