20160412

Physics quiz question: resistive element with most current

Physics 205B Quiz 4, spring semester 2016
Cuesta College, San Luis Obispo, CA

Two different types of light bulbs, a resistor, and an ideal emf source are connected together. The __________ has the most current flowing through it.
(A) 0.50 Ω light bulb.
(B) 0.80 Ω light bulb.
(C) resistor.
(D) (There is a two-way tie.)
(E) (There is a three-way tie.)
(F) (Not enough information is given.)

Correct answer (highlight to unhide): (B)

From Kirchhoff's junction rule, the current flowing through the 0.80 Ω light bulb is the same as the current flowing through the emf, as they are in series with each other. After flowing out of the positive terminal of the emf, the current then encounters a junction at the left of the circuit diagram, where part of it would then flow through the 0.50 Ω light bulb, while the remainder of the current would flow through the resistor, which are wired in parallel with each other. Since the current that flows through the 0.80 Ω light bulb and the emf is divided between the parallel 0.50 Ω light bulb and resistor, then of all the resistive elements in the circuit, the 0.80 Ω light bulb has the most current flowing through it.

Sections 30882, 30883
Exam code: quiz04T4nK
(A) : 13 students
(B) : 4 students
(C) : 3 students
(D) : 9 students
(E) : 7 students
(F) : 0 students

Success level: 11%
Discrimination index (Aubrecht & Aubrecht, 1983): –0.04

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