Practice Series Circuit in Physics

Use these practice problems to test your method after reviewing the concept explanation and worked examples.

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Quick Recap

A circuit arrangement in which components are connected end-to-end along a single path, so exactly the same current flows through every component.

Like cars on a single-lane road — every car (charge) must pass through every toll booth (component) in order.

Showing a random 20 of 50 problems.

Example 1

medium
Three resistors in series share 18 V18 \text{ V}. Two of them are equal and each dissipate 4 V4 \text{ V}. What voltage is across the third resistor?

Example 2

challenge
A series circuit with a 99 V battery and total resistance RR carries 0.60.6 A. A 3 Ω3\,\Omega resistor is then added in series. What is the new current?

Example 3

medium
A 2020 V source drives 5 Ω5\,\Omega and 5 Ω5\,\Omega in series. Find the current.

Example 4

medium
A 2424 V battery drives 4 Ω4\,\Omega and 8 Ω8\,\Omega in series. Find the current and the voltage across the 8 Ω8\,\Omega resistor.

Example 5

hard
A series circuit has a 5 Ω5 \text{ } \Omega resistor and a 10 Ω10 \text{ } \Omega resistor across a battery of unknown emf. The 10 Ω10 \text{ } \Omega resistor dissipates 4 W4 \text{ W}. Find the loop current and the emf.

Example 6

medium
A 12 V12 \text{ V} battery drives a 4 Ω4 \text{ } \Omega resistor in series with an unknown RR. The current is 1.5 A1.5 \text{ A}. Find RR.

Example 7

easy
Will adding more resistors in series cause the total current to increase or decrease (same battery)?

Example 8

medium
A 24 V24 \text{ V} battery drives resistors R1=2 ΩR_1 = 2 \text{ } \Omega, R2=4 ΩR_2 = 4 \text{ } \Omega, R3=6 ΩR_3 = 6 \text{ } \Omega in series. Find (a) the current and (b) the voltage across R3R_3.

Example 9

hard
Design a voltage divider using two series resistors to drop a 12 V12 \text{ V} source down to 4 V4 \text{ V} across the lower resistor, with a total current of 10 mA10 \text{ mA}.

Example 10

easy
A 9 V9 \text{ V} battery drives three identical resistors in series. What voltage appears across each?

Example 11

easy
In a series circuit, is the current the same through every component?

Example 12

easy
Four identical 3 Ω3 \text{ } \Omega resistors are in series. What is the total resistance?

Example 13

medium
A 1010 V source feeds 2 Ω2\,\Omega, 3 Ω3\,\Omega, and 5 Ω5\,\Omega in series. What is the voltage across the 3 Ω3\,\Omega resistor?

Example 14

challenge
Old-style Christmas lights have 5050 identical bulbs in series across a 120 V120 \text{ V} supply. Each bulb dissipates 1.2 W1.2 \text{ W} at its operating point. Find the current and the resistance of each bulb at operation.

Example 15

medium
In a series circuit with two bulbs, one bulb burns out (open). Does the other still light?

Example 16

easy
Resistors of 3 Ω3 \text{ } \Omega, 4 Ω4 \text{ } \Omega, and 5 Ω5 \text{ } \Omega are in series. What is the total resistance?

Example 17

hard
A 6 V6 \text{ V} battery drives resistors R1=2 ΩR_1 = 2 \text{ } \Omega and R2=4 ΩR_2 = 4 \text{ } \Omega in series. The battery has internal resistance 1 Ω1 \text{ } \Omega. Find the terminal voltage of the battery.

Example 18

medium
A series circuit has 3 Ω3\,\Omega and 6 Ω6\,\Omega resistors and a current of 22 A. What is the source voltage?

Example 19

challenge
Two resistors in series across 2020 V give drops in the ratio 2:32:3. Find both drops, and if the smaller resistor is 4 Ω4\,\Omega, the current.

Example 20

easy
Resistors 5 Ω5\,\Omega and 7 Ω7\,\Omega are in series. Find the total resistance.
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