Question

A parallel circuit contains four identical lamps. The current through the energy source is 4 A. The total resistance of the circuit is 10 Ω. What is the voltage across the energy source and across each lamp?

a)2.5 V; 40 V
b)40 V; 40 V
c)2.5 V; 2.5 V
d)40 V; 2.5 V

Answer 1

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Step-by-step explanation:

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Answer 2

b. 40V , 40V

Step-by-step explanation:

Connections are as per the figure.

As total current through source is 4A , current through each lamp is 1A.

As total resistance of the circuit is 10Ω ,resistance of each bulb is 40Ω because in case of a parallel circuit in which identical objects are connected ,
`R_(eff) = (R)/(n)` where R is the resistance of each bulb and n is the number of bulbs.

As per Ohm's law , voltage of the source =IR = 4×10 =40V.

We can see from the figure that if the voltage across the source is 40V , the voltage across each bulb is also 40V.