Practice Pakistan's most useful MCQs for competitive exams

In a certain three-branch parallel circuit, R1 has 12 mA through it, R2 has 15 mA through it, and R3 has 25 mA through it. After measuring a total of 27 mA, you can say that____________?

• (A)  R3 is open
• (B)  R1 is open
• (C)  R2 is open
• (D)  the circuit is operating properly

Answer

Submitted By :Ali Uppal

Five 100 Ω resistors are connected in parallel. If one resistor is removed, the total resistance is______________?

• (A)  25 Ω
• (B)  500 Ω
• (C)  100 Ω
• (D)  20 Ω

Answer

Submitted By :Ali Uppal

One condition for oscillation is_____________?

• (A)  A phase shift around the feedback loop of 180o
• (B)  A gain around the feedback loop of one-third
• (C)  A phase shift around the feedback loop of 0o
• (D)  A gain around the feedback loop of less than 1

Answer

Submitted By :Ali Uppal

The total resistance of a parallel circuit is 50 Ω. If the total current is 120 mA, the current through the 270 Ω that makes up part of the parallel circuit is approximately_______________?

• (A)  22 mA
• (B)  120 mA
• (C)  220 mA
• (D)  50 mA

Answer

Submitted By :Ali Uppal

The crystal oscillator frequency is very stable due to___________of the crystal?

• (A)  Rigidity
• (B)  Vibrations
• (C)  Low Q
• (D)  High Q

Answer

Submitted By :Ali Uppal

In an LC circuit, when the capacitor is maximum, the inductor energy is____________?

• (A)  Minimum
• (B)  Maximum
• (C)  Half-way between maximum and minimum
• (D)  None of the above

Answer

Submitted By :Ali Uppal

The output impedance of an emitter follower is______________?

• (A)  High
• (B)  Very high
• (C)  Almost zero
• (D)  Low

Answer

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A Wien bridge oscillator uses___________feedback?

• (A)  Only positive
• (B)  Only negative
• (C)  Both positive and negative
• (D)  None of the above

Answer

Submitted By :Ali Uppal

Quartz crystal is most commonly used in crystal oscillators because:____________?

• (A)  It has superior electrical properties
• (B)  It is easily available
• (C)  It is quite inexpensive
• (D)  None of the above

Answer

Submitted By :Ali Uppal

There is a total of 800 mA of current into four parallel resistors. The currents through three of the resistors are 40 mA, 70 mA, and 200 mA. The current through the fourth resistor is______________?

• (A)  490 mA
• (B)  800 mA
• (C)  310 mA
• (D)  0 A

Answer

Submitted By :Ali Uppal