Electronics - Series Circuits - Discussion

Case 1: When lamp is in series with 8ohm resistor

Case 2: The lamp is removed from circuit and asking the drop across lamp hoder.

Here when lamp is remove it is like circuit is open circuited at lamp place.

So the drop across open circuit will be equal to source voltage or we can consider it also as drop across 8ohm resistor

Vr=(20/8)x8 = 20V

Drop = 20V

If lamp is in circuit then circuit is complete and current is flow and voltage is drop across each components, but in given Q. the lamp is remove then circuit. is open at that point.

So source voltage is equal to lamp and points, becouse circuit is Series circuit. So option (D)will be right.

Answer D is correct because when bulb is removed, there is not any resistance (open ckt) and voltmeter doesn't take any current, hence current through the ckt is zero and there won't be any drop across 8-ohm resister, so all the voltage will be shown by voltmeter.

D Answer is correct B'coz

v=IR so by calculation I=4 amp so whn lamp is removed there wnt b ny resistance thats why v=0 thus at d lamp circuit it w'll read 20v voltage.

Answer D is correct
In open circuit no current flows so voltmeter shows source voltage (20v)