Electrical Engineering - Series-Parallel Circuits - Discussion

Please, anyone explain it clearly to understand.

The higher the rating of V meter, the higher its internal resistance. Since V meter is connected in parallel in circuit, to have minimum loading effect the V meter should have high internal resistance so that minimum amount of circuit current can pass through it. Thus, among the four options, the highest rating V meter is 1000V and thus it will result in minimum withdrawal of circuit current.

@All.

A voltmeter's setting is made in terms of Ohm/V.

So, for sensitive circuits, the voltmeter will draw minimum current when its resistance is maximum which will be for V=1000V available in options.

For example, if Voltmeter sensitivity is 1000 Ohm/V then for 1000 Volt, its resistance will be 1000 * 1000 = 1000000 Ohm and it will draw negligible current.
That's it.

@Puja.

The voltage is inversely proportional to load. So the minimum load has maximum voltage so the answer is max voltage that is 1000V.

Anybody can tell me V=IR then how voltage is inversely proportional to current?

Consider formula P = V*I hence V is inversely proportional to current while load consideration.

It is given that in which of the following options voltmeter presents a minimum load means here the voltmeter is behaving as a load. For more and more voltages the coil in the voltmeter has low value.

For example take a voltage divider. If the voltage setting is less than full voltage appears across the load.

In the same way when coil resistance is low full voltage will be appeared across load that means the voltmeter is not much acting as a load. So 1000v is correct. If in options any value which is given more than that then it will be correct.

When voltage increase current is decrease so answer d is correct because it is highest voltage in given option.

By ohms law we know that current is directly proportional to voltage and inversely proportional to resistance. Adding load means adding resistance we all know that when resistance is high, current is low when resistance is low current is high.

So here resistance is low means current is high which is directly proportional to voltage so answer is max in given options 1000 is max.

@Yamini.

No its not possible to measure the load with voltage which is present by a voltmeter. But its true.

Voltage is inversely proportional to load on the system i.e. as load increases voltage decreases. But we can't measure individual voltmeter we need flowing current or opposing resistance.