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# CoCubes Previous Questions in Electronics

Q1.In case of current shunt feedback amplifier, what will happen to the input resistance and output resistance?

• Input resistance increases and output resistance decreases
• Input resistance decreases and output resistance increases
• Both Input resistance and output resistance decreases
• Both Input resistance and output resistance increases

Ans:Input resistance decreases and output resistance increases

Q2.In a certain transistor, the emitter current is 1.08 times as large as the collector current. If it is known that the emitter current is 10 mA, determine the base current.

• 0.74 mA
• 0.46 mA
• 0.32 mA
• 0.98 mA

Ans:0.74 mA

Q3.Why does the gain of a BJT drop at high frequencies?

• Because of the inter-electrode capacitances (transistor capacitances)
• Because of the early effect
• Because of the high current effects in the base
• None of the mentioned options

ans:Because of the inter-electrode capacitances (transistor capacitances)

Q4.For the transistor given below, if = 50, then determine the value of voltage “VEC“. • 6.16 V
• 8.24 V
• 3.42 V
• 10.24 V

Ans: 6.16 V

Q5.Two incandescent light bulbs of 30 W and 50 W rating are connected in series across the supply voltage “V”, then:

• the bulbs together will consume 80 W
• the bulbs together will consume 20 W
• the 50 W bulb glows brighter
• the 30 W bulb glows brighter

Ans: the 50 W bulb glows brighter

Q6. Determine the value of “E”

• -16 V
• -18V
• -20V
• -21V

Ans: -18V

Q7. Determine resistance across “ab”.

• 3.24 ohm
• 6.22 ohm
• 2.08 ohm
• 8.22 ohm

Ans:3.24 ohm

Q8.In the following circuit, i1 = 2 sin 4t A and i2 = 5 sin 3t A. Determine the value of “v1“. • 32 cos 4t + 15 cos 3t
• 15 cos 4t + 32 cos 3t
• 32 cos 3t + 32 cos 2t
• 32 cos 3t – 15 cos 2t

ans: 32 cos 4t + 15 cos 3t

Q9 Determine the value of “Vx“.

• -9.6 V
• -6.8 V
• -4.2 V
• -12.3 V

Ans: -12.3 V

Q10.Which of the following signals is used to read the opcode from the data bus and execute it?

• INTR
• INTA
• HLDA
• (RESET IN)’

Ans:INTA

Q11.If both of the status signals of a 8085 microprocessor are high, then which of the following operations can be performed?

• Halt
• Write
• Fetch

Ans: Fetch

Q12.For the given code, if the contents of memory location 4A00H, 4A001H and 4A002H are respectively A8H, 97H and 46H, then after execution of program contents of memory location 4A02H will be:

``` LXI H, 4A02H LDA 4A00H MOV B, A LDA 4A01H CMP B JZ FNSH JC GRT MOV M, A JMP FNSH MOV M, B FNSH: HLT```

• A8H
• 97H
• 46H
• None of the mentioned options

Ans :A8H

Q13.For the given code, if the content in the memory location 4400H is 44H before the execution of the program, then content in memory location 4300H after the execution of the program will be:

```LDA 4400H CMA STA 4300H HLT```

• BBH
• AAH
• ABH
• BAH

Ans: BBH

Q14. The given diode logic circuit represents:

• OR gate
• NAND gate
• NOR gate
• AND gate

Ans OR gate

• EE
• DD
• F0
• E0

Ans: F0

Q16.The hexadecimal number “A1” has the decimal value equivalent to:
• 81
• 161
• 257
• 177

Ans: 161

Q17.If the input to T-flip-flop is 120 Hz signal, then the final output of the three T-flip-flops in cascade will be:

• 15 Hz
• 18.5Hz
• 12.5Hz
• 5oHz

Ans: 15Hz

Q18. The Boolean function realized by the logic circuit shown below will be: • F = m(2, 3, 6, 7, 8, 10, 12)
• F = m(2, 3, 5, 7, 10, 12, 13)
• F = m(1, 3, 6, 8, 9, 11, 12)
• F = m(1, 3, 5, 7, 9, 10, 12)

Ans: F = m(2, 3, 6, 7, 8, 10, 12)

Q19.Which of the following modulation schemes is digital in nature?

• Pulse Amplitude Modulation
• Pulse Position Modulation
• Pulse Width Modulation
• Delta Modulation

Ans: Delta Modulation

Q20.Which of the following statements is/are the disadvantages of time division multiplexing?

I. It has large amount of crosstalk problem.
II. Synchronization is required for proper operation.
III. There are possibilities of loss of TDM signal due to channel noise.

Choose the correct answer from the options given below.

• Both I and II
• Both II and III
• Both I and III
• I, II and III

Ans:Both II and III

### 3 comments on “CoCubes Previous Questions in Electronics”

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