Question 1
A D flip-flop is used in a 4-bit serial adder, why?
A. It is used to invert the input of the full adder
B. It is used to store the output of the full adder
C. It is used to store the carry output of the full adder
D. It is used to store the sum output of the full adder
View Answer
Answer: Option C
Explanation:
The D flip-flop, i.e. carry flip-flop, is used to store the carry output of the full adder so that it can be added to the next significant position of the numbers in the registers.
Question 2
A serial subtractor can be obtained by converting the serial adder by using the _____________
A. 1’s complement system
B. 2’s complement system
C. 10’s complement
D. 9’s complement
View Answer
Answer: Option B
Explanation:
A serial subtractor can be obtained by converting the serial adder by using the 2’s complement system. 9’s complement and 10’s complement are used for decimal numbers while adders deal with binary numbers.
Question 3
How many NOT gates are required to implement the Boolean expression: X = AB’C + A’BC?
A. 2
B. 3
C. 4
D. 5
View Answer
Answer: Option A
Explanation:
Since in the given expression two inputs are complemented. So, we require two NOT gate at the input. A NOT gate is a basic gate which accepts a single input and produces a single output, which is the inverted version of the input.
Question 4
How many shift registers are used in a 4 bit serial adder?
A. 4
B. 3
C. 2
D. 5
View Answer
Answer: Option C
Explanation:
There are two shift registers are used in a 4-bit serial adder, which is used to store the numbers to be added serially. Serial addition takes place bit by bit.
Question 5
If minuend = 0, subtrahend = 1 and borrow input = 1 in a full subtractor then the borrow output will be __________
A. 0
B. 1
C. Floating
D. High Impedance
View Answer
Answer: Option B
Explanation:
If minuend = 0, subtrahend = 1 and borrow input = 1 in a full subtractor then the borrow output will be 1. Because on subtracting 0 and 1, one borrow is taken and it proceeds till the next step (i.e 0 – 1 – 1 = 0, borrow = 1).
Question 6
In most applications, transistor switches used in place of relays?
A. They consume less power
B. They are faster
C. They are quieter and smaller
D. All of the Mentioned
View Answer
Answer: Option D
Explanation:
Transistors are of less consuming power, faster, quieter, smaller and its implementation is too easy. So, in most applications transistor switches are more preferred. And also, transistors can be current-controlled or voltage-controlled depending on our choice.
Question 7
In serial addition, the addition is carried out __________
A. 3 bit per second
B. Byte by byte
C. Bit by bit
D. All bits at the same time
View Answer
Answer: Option C
Explanation:
In serial addition, the addition is carried out bit by bit.
Question 8
Internally, a computer’s binary data are always transmitted on parallel channels which is commonly referred to as the __________
A. Parallel bus
B. Serial bus
C. Data bus
D. Memory bus
View Answer
Answer: Option C
Explanation:
A process consists of 3 types of buses: Control Bus, Data Bus and Address Bus. A computer’s data is always in the binary form which is stored in the bus that transmits the data on any channels. It doesn’t matter that it’s in parallel or serial.
Question 9
One positive pulse with tw = 75 µs is applied to one of the inputs of an exclusive-OR circuit. A second positive pulse with tw = 15 µs is applied to the other input beginning 20 µs after the leading edge of the first pulse. Which statement describes the output’s relation with the inputs?
A. The exclusive-OR output is a 20 s pulse followed by a 40 s pulse, with a separation of 15 s between the pulses
B. The exclusive-OR output is a 20 s pulse followed by a 15 s pulse, with a separation of 40 s between the pulses
C. The exclusive-OR output is a 15 s pulse followed by a 40 s pulse
D. The exclusive-OR output is a 20 s pulse followed by a 15 s pulse, followed by a 40 s pulse
View Answer
Answer: Option D
Explanation:
When both the input pulses are high or low X-OR output is low. But when one of the input is high and another is low or vice-versa, output is high. In this problem for the first 20uS one input is high and another is low. So, obviously output is a high. for next 15uS both the input is high so output is low and for remaining 40uS(75-20-15) first input is still high and second one is low so output is high.
Question 10
Serial communication can be sped up by __________
A. Using silver or gold conductors instead of copper
B. Using high-speed clock signals
C. Adjusting the duty cycle of the binary information
D. Using silver or gold conductors instead of copper and high-speed clock signals
View Answer
Answer: Option B
Explanation:
For any serial data transmission there is required of continuously data supply and if the input supply (i.e. high speed clock signals) in a high amount the speed of serial communication can be increased. In serial communication, data is transmitted bit by bit. So the use of high speed clock pulses would make the process faster.
Question 11
The hexadecimal number (4B)16 is transmitted as an 8-bit word in parallel. What is the time required for this transmission if the clock frequency is 2.25 MHz?
A. 444 ns
B. 444 s
C. 3.55 s
D. 3.55 ms
View Answer
Answer: Option A
Explanation:
Because the clock pulse of 4-bit transmits the data of 8-bit word in parallel mode and this transmission is done at 2.25 MHz frequency. We know that: f=1/t and we can find the time required for this transmission by the clock pulse.Therefore, time = (1/2.25) = 0.4444 us = 444.44 ns ~ 444ns.
Question 12
The inverter can be produced with how many NAND gates?
A. 2
B. 1
C. 3
D. 4
View Answer
Answer: Option B
Explanation:
The inverter can be produced with the help of single NAND gate, because we can send a single input twice through the same NAND gate together, thus producing the inverted version of the input as output. It works as an inverter.
Question 13
The serial format for transmitting binary information uses __________
A. A single conductor
B. Multiple conductors
C. Infrared technology
D. Fiber-optic
View Answer
Answer: Option A
Explanation:
A conductor accepts the whole data and arranges it in a serial manner, which is transmitted as binary information. In serial transmission, data is transmitted bit by bit while in parallel transmission data is transmitted simultaneously.
Question 14
What are carry generate combinations?
A. If all the input are same then a carry is generated
B. If all of the output are independent of the inputs
C. If all of the input are dependent on the output
D. If all of the output are dependent on the input
View Answer
Answer: Option B
Explanation:
If the input is either 0, 0, 0 or 0, 0, 1 then the output will be 0 (i.e. independent of input) and if the input is either 1, 1, 0 or 1, 1, 1 then the output is 1 (i.e independent of input). Such situation is known as carry generate combinations.
Question 15
What is ripple carry adder?
A. The carry output of the lower order stage is connected to the carry input of the next higher order stage
B. The carry input of the lower order stage is connected to the carry output of the next higher order stage
C. The carry output of the higher order stage is connected to the carry input of the next lower order stage
D. The carry input of the higher order stage is connected to the carry output of the lower order stage
View Answer
Answer: Option A
Explanation:
When the carry output of the lower order stage is connected to the carry input of the next higher order stage, such types of connection is called ripple carry adder in a 4-bit binary parallel adder.
Question 16
What is the frequency of a clock waveform if the period of that waveform is 1.25sec?
A. 8 kHz
B. 0.8 kHz
C. 0.8 MHz
D. 8 MHz
View Answer
Answer: Option C
Explanation:
By using the formula of frequency, we can find the frequency of clock waveform. Time period(t) of the waveform is = 1.25microseconds f=1/t Where ‘t’ is the time taken by the clock waveform; f=(1/1.25) so, f=0.8 MHz.
Question 17
Why is parallel data transmission preferred over serial data transmission for most applications?
A. It is much slower
B. It is cheaper
C. More people use it
D. It is much faster
View Answer
Answer: Option D
Explanation:
Parallel data transmission preferred over serial data transmission for most applications because it is much faster as bits are transmitted simultaneously, whereas in serial data transmission, bits are transmitted one by one.
Question 18
With surface-mount technology (SMT), the devices should __________
A. Utilize transistor outline connections
B. Mount directly
C. Have parallel connecting pins
D. Require holes and pads
View Answer
Answer: Option B
Explanation:
Surface-mount technology (SMT) is a method for producing electronic circuits in which the components are mounted or placed directly onto the surface of printed circuit boards (PCBs). An electronic device so made is called a surface-mount device (SMD). In the industry, it has largely replaced the through-hole technology construction method of fitting components with wire leads into holes in the circuit board. Both technologies can be used on the same board for components not suited to surface mounting such as large transformers and heat-sinked power semiconductors.