CET DC Circuit Analysis & Theory 2

Question 1

Three resistors of 10 Ω, 20 Ω, and 30 Ω are connected in series across a 120 V supply. What is the voltage drop across the 20 Ω resistor?

Accepted Answer

40 V

Answer

Total resistance is 60 Ω; current = 2 A; V = 2 A × 20 Ω = 40 V.

Question 2

Which law states that the algebraic sum of all voltages around any closed loop in a circuit equals zero?

Accepted Answer

Kirchhoff's Voltage Law

Answer

Kirchhoff's Voltage Law (KVL) states that the sum of EMFs equals the sum of voltage drops around any closed loop.

Question 3

A 60 W lamp operates at 120 V. What is its resistance?

Accepted Answer

240 Ω

Answer

R = V²/P = 120²/60 = 14400/60 = 240 Ω.

Question 4

In a voltage divider with R1 = 4 kΩ and R2 = 1 kΩ connected to 25 V, what is the output voltage across R2?

Accepted Answer

5 V

Answer

Vout = Vin × R2/(R1+R2) = 25 × 1/5 = 5 V.

Question 5

What happens to total resistance when additional resistors are added in series?

Accepted Answer

Increases

Answer

Series resistances add directly, so total resistance always increases with each addition.

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