A galvanometre coil has a resistance of 15ohm and it's show a full scale deflection for a current of 4mA. how will you convert the galvanometer into an ammeter of range 0to6A and a voltmeter of range 0to50V
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To convert into Ammeter you need to connect an additional resistance(R) parallel to the galavanometer.
To find the value of that parallel resistance,
I = 6A and galvanometer can only handle 4mA
So current left is 5996mA
When connected in parallel, potential difference across both will be same.
5996(R) = 4 × 15
R = 0.01 ohms (approximately.)
For converting to Voltmeter we have to connect additional resistance(R) in series to the galvanometer.
Now current will be same since they are in series. Note : G is the resistance of galvanometer.
50 = (4×10^(-3))(R + G)
R + G = 12500 ohms
Thus
R = 12500 - 15 = 12485 ohms
To find the value of that parallel resistance,
I = 6A and galvanometer can only handle 4mA
So current left is 5996mA
When connected in parallel, potential difference across both will be same.
5996(R) = 4 × 15
R = 0.01 ohms (approximately.)
For converting to Voltmeter we have to connect additional resistance(R) in series to the galvanometer.
Now current will be same since they are in series. Note : G is the resistance of galvanometer.
50 = (4×10^(-3))(R + G)
R + G = 12500 ohms
Thus
R = 12500 - 15 = 12485 ohms
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