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2064 Q.No. 1 Ammeter are always connected in senes in a electrical circuit, wh/?
2063 (Baisakh] Q.No. 1 Voltmeters are always connected in parallel in an electric arcu
why?
2063 (Aswini Q.No. 17 How the galvanometer is converted into voltmeter
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Answers
Answer:
1.Ammeter is a device obtained by connecting a very small resistance in parallel with galvanometer. Since, in parallel combination the equivalent resistance of the combination is always less than the smallest resistance, hence, the ammeter has negligibly small resistance. Due to this it allows the passage of maximum(almost equal) of main current in circuit and hence, it is connected in the series in a circuit to read the accurate current reading.
2.Voltmeter is always connected in parallel because it has high internal resistance. A voltmeter, in reality, only needs a very small amount of current to measure the potential difference between its ends, hence the need to have a very high internal resistance.
3.Voltmeter is an electrical measuring device, which is used to measure potential difference between two points in a circuit. Voltmeter is always connected in parallel to a circuit.
Since Galvanometer is a very sensitive instrument, therefore it can not measure high potential difference. In order to convert a Galvanometer into voltmeter, a very high resistance known as "series resistance" is connected in series with the galvanometer.