identify which of the following voltmeter should be selected for most accurate reading?
1)100 V, 1 A
2)100 V, 100 ohms/volt
3)100 V, 100 mA
4)100 V, 1 mA
Answers
Answer:-
We will choose 2) 100V, 100ohms volt metre.
Explanation:-
In order to get correct reading from voltmeter, it should have maximum resistance. Voltmeter is always connected in parellel connection to measure potential difference across 2 terminals but it should not change current at any terminal. An ideal voltmeter has infinite resistance, so that current may not flow through it. If current is flowing through the voltmeter, it would not measure correct reading.
It is given in option 2) that resistance is very high (100 ohms) so it an ideal voltmeter and it will measure correct reading.
Hence option 2) is correct.
For most accurate reading voltmeter should be 100V, 100volt/ohms.
Explanation:
Voltmeter measures the voltage difference between two points but it does not adjust the amount of current passing between the two points therefore, they have high resistance so that current does not draw through it.
For more accurate reading we have to increase the input impedence of voltmeter. So, in option we have highest voltage 100V .
Because of high resistance, current will have to be minimum i.e. 100 volt/ohm .