## Series Circuits MCQ (Interview-Exam) Question-Answer

**Q.1** Find the current in the circuit.

**A.** 2 A

**B.** 4 A

**C.** 1 A

**D.** 3 A

**Ans : **2 A

**Explanation: ** I=V/R. Total resistance R = 20+40=60ohm. V=120V. I=120/60=2A.

**Q.2** In a series circuit, which of the parameters remain constant across all circuit elements such as resistor, capacitor and inductor etcetera?

**A.** Current

**B.** Both voltage and current

**C.** Voltage

**D.** None of them

**Ans : **Current

**Q.3** Find the voltage across the 6 ohm resistor.

**A.** 181.6V

**B.** 54.48V

**C.** 150V

**D.** 27.27V

**Ans : **27.27V

**Explanation: ** Total current I=150/(6+12+15)=(150/33)V.

V across 6 ohm = 6*I = 6*(150/33)V = 27.27V.

**Q.4** Voltage across the 60ohm resistor is______.

**A.** 0V

**B.** 120V

**C.** 72V

**D.** 48V

**Ans : **0V

**Explanation: ** The 60ohm resistance is shortened because the current always chooses the low resistance path. The voltage in a short circuit is equal to zero, so the voltage across the resistor is 0.

**Q.5** What is the value of x if the current in the circuit is 5A?

**A.** 25 ohm

**B.** 75 ohm

**C.** 15 ohm

**D.** 55 ohm

**Ans : **15 ohm

**Explanation: ** Total voltage=sum of voltages across each resistor. =>150=10*5+5*5+5*x. Solving the equation, we get x=15 ohm.

**Q.6** If there are two bulbs connected in series and one blows out, what happens to the other bulb?

**A.** The other bulb stops glowing

**B.** The other bulb glows with increased brightness

**C.** The other bulb continues to glow with the same brightness

**D.** The other bulb also burns out

**Ans : **The other bulb stops glowing

**Q.7** Many resistors connected in series will?

**A.** Divide the current proportionally

**B.** Reduce the power to zero

**C.** Divide the voltage proportionally among all the resistors

**D.** Increase the source voltage in proportion to the values of the resistors

**Ans : **Divide the voltage proportionally among all the resistors

**Q.8** A voltage across a series resistor circuit is proportional to?

**A.** The value of the resistance itself

**B.** The power in the circuit

**C.** The amount of time the circuit was on for

**D.** The value of the other resistances in the circuit

**Ans : **2 A

**Q.9** What happens to the current in the series circuit if the resistance is doubled?

**A.** It becomes double its original value

**B.** It becomes infinity

**C.** It becomes half its original value

**D.** It becomes zero

**Ans : **It becomes half its original value

**Q.10** What is the voltage measured across a series short?

**A.** Zero

**B.** Null

**C.** Infinite

**D.** The value of the source voltage

**Ans : **Zero

## Series Circuits in Electrical Engineering

**Single Path for Current:**In a series circuit, all components (resistors, capacitors, inductors, etc.) are connected in a single path, forming a continuous loop.**Same Current Through All Components:**The same current flows through all components in a series circuit. This is a characteristic of series circuits.**Voltage Divides Across Components:**The total voltage supplied is divided among the components in proportion to their resistance. The voltage across each component adds up to the total voltage.**Resistance Adds Up:**The total resistance in a series circuit is the sum of the individual resistances of each component. \(R_{\text{total}} = R_1 + R_2 + \ldots + R_n\)**Current is Constant:**Since there is only one path for current flow, the same current passes through each component. It remains constant throughout the circuit.**If One Component Fails:**If one component in a series circuit fails (opens), the entire circuit is broken, and current cannot flow.**Applications in Voltage Dividers:**Series circuits are often used in voltage divider circuits, where the input voltage is divided into different proportions across resistors.**Analytical Calculations:**Analyzing a series circuit is relatively straightforward using Kirchhoff’s voltage law and Ohm’s law. These laws help in determining the current, voltage, and resistance relationships in the circuit.**Limited in Practical Applications:**While series circuits are useful for certain applications, they are less common in practical electrical systems due to their vulnerability to complete failure if one component malfunctions.**Battery Cells in Series:**Connecting batteries in series increases the total voltage output while maintaining the same current. This configuration is often used to power devices requiring higher voltage.