Three bulbs, each with a resistance of 180 , are connected in parallel to an ideal battery of emf 60 V . Determine the current delivered by the battery when all the bulbs are switched on.

Correct answer: D. 1.0 A Given the resistance of each bulb, R = 180 . Since three such bulbs are connected in parallel, the equivalent resistance R_ eq of the circuit is given by: 1 R_ eq = (1)/(R) + (1)/(R) + (1)/(R) = (3)/(R) R_ eq = (R)/(3) = (180)/(3) = 60 The emf of the ideal battery is V = 60 V . According to Ohm's law, the total current I delivered by the battery is: I = V R_ eq = (60)/(60) = 1.0 A

Concepts Of Physics MCQ Edition [Volume 2]

Exam: Concepts Of Physics MCQ Edition [Volume 2]
Subject: Physics
Chapter: Electric Current in Conductors

Concepts Of Physics MCQ Edition [Volume 2] · Physics · Electric Current in Conductors

Three bulbs, each with a resistance of 180 , are connected in...

Three bulbs, each with a resistance of

180 \Omega

, are connected in parallel to an ideal battery of emf

60 \text{ V}

. Determine the current delivered by the battery when all the bulbs are switched on.

Options

A $0.67 \text{ A}$
B $0.33 \text{ A}$
C $3.0 \text{ A}$
D $1.0 \text{ A}$

Correct answer

D. $1.0 \text{ A}$

Step-by-step solution

Given the resistance of each bulb,

R = 180 \Omega

.

Since three such bulbs are connected in parallel, the equivalent resistance

R_{eq}

of the circuit is given by:

\dfrac{1}{R_{eq}} = \dfrac{1}{R} + \dfrac{1}{R} + \dfrac{1}{R} = \dfrac{3}{R}

R_{eq} = \dfrac{R}{3} = \dfrac{180}{3} = 60 \Omega

The emf of the ideal battery is

V = 60 \text{ V}

.

According to Ohm's law, the total current

I

delivered by the battery is:

I = \dfrac{V}{R_{eq}} = \dfrac{60}{60} = 1.0 \text{ A}

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