Introduction to Computer Science: Basic Concepts and Data Representation Quiz

1. Assuming that each of the following bit patterns originally had even parity, which one contains an error?

100001011

100000001

100001000

100001001

In a bit pattern with even parity, the total number of ones is always even. In the correct answer, 100001001, there are a total of 4 ones, which is even. In the incorrect answers, the total number of ones is odd, indicating an error in the parity.

Explanation

In a bit pattern with even parity, the total number of ones is always even. In the correct answer, 100001001, there are a total of 4 ones, which is even. In the incorrect answers, the total number of ones is odd, indicating an error in the parity.

2. Which of the following data storage systems provides the most efficient random access to individual data items?

External SSD

Hard disk drive

Cloud storage

Main memory

Main memory, also known as RAM (Random Access Memory), provides the most efficient random access to individual data items compared to hard disk drives, cloud storage, and external SSDs.

Explanation

Main memory, also known as RAM (Random Access Memory), provides the most efficient random access to individual data items compared to hard disk drives, cloud storage, and external SSDs.

3. Which of the following bit-patterns represents the smallest positive value using the floating-point format in which the most significant bit is the sign bit, the next three bits represents the exponent field in excess notation, and the last four bits represents the mantissa?

01001011

00000000

01111111

00101000

The smallest positive value in floating-point format is achieved by having a sign bit of 0, an exponent field representing a small negative value in excess notation, and a mantissa that is not all zeros or ones, which is why the correct answer is 00101000.

Explanation

The smallest positive value in floating-point format is achieved by having a sign bit of 0, an exponent field representing a small negative value in excess notation, and a mantissa that is not all zeros or ones, which is why the correct answer is 00101000.

4. Which of the following bit patterns (represented in hexadecimal notation) do NOT represent a negative number in two's complement notation?

A6

F8

D3

5B

In two's complement notation, the most significant bit (leftmost) indicates the sign of the number. If it is '1', the number is negative. A6 has a leftmost bit of '1', making it a negative number.

Explanation

In two's complement notation, the most significant bit (leftmost) indicates the sign of the number. If it is '1', the number is negative. A6 has a leftmost bit of '1', making it a negative number.

5. Which of the following provides a compressed representation of an image by limiting the number of different pixel colors to 256, thereby enabling each pixel in an image to be represented by a single?

PNG

BMP

GIF

JPEG

GIF files use a palette of 256 colors to represent images, which allows for smaller file sizes. JPEG files use a lossy compression algorithm to reduce file size. PNG files support more colors and transparency compared to GIF. BMP files store graphics without compression, leading to larger file sizes.

Explanation

GIF files use a palette of 256 colors to represent images, which allows for smaller file sizes. JPEG files use a lossy compression algorithm to reduce file size. PNG files support more colors and transparency compared to GIF. BMP files store graphics without compression, leading to larger file sizes.

6. Which of the following is a means of encoding music?

MP4

MIDI

PDF

JPEG

MIDI (Musical Instrument Digital Interface) is a standard protocol used for encoding music and controlling electronic musical devices. It allows for communication between different musical instruments and devices. JPEG, MP4, and PDF are file formats used for images, videos, and documents respectively, not music encoding.

Explanation

MIDI (Musical Instrument Digital Interface) is a standard protocol used for encoding music and controlling electronic musical devices. It allows for communication between different musical instruments and devices. JPEG, MP4, and PDF are file formats used for images, videos, and documents respectively, not music encoding.

7. Which of the following is the binary representation of 4 5/8?

100,101

110,101

100,110

001,011

To convert 4 5/8 to binary, first convert the whole number part 4 to binary as 100. Then convert the fractional part 5/8 to binary which is 101. Combine both parts to get the binary representation 100,101.

Explanation

To convert 4 5/8 to binary, first convert the whole number part 4 to binary as 100. Then convert the fractional part 5/8 to binary which is 101. Combine both parts to get the binary representation 100,101.

8. What is the result of the following subtraction problem (using two's complement notation)? 00001111 - 10101010

00100101

11011010

10011011

01100010

When subtracting in two's complement notation, you first do the subtraction as if it were unsigned. Then take the two's complement of the result if the original second number was negative. In this case, 00001111 - 10101010 results in 10100101. Since the second number was negative, taking the two's complement gives us 01100010.

Explanation

When subtracting in two's complement notation, you first do the subtraction as if it were unsigned. Then take the two's complement of the result if the original second number was negative. In this case, 00001111 - 10101010 results in 10100101. Since the second number was negative, taking the two's complement gives us 01100010.

9. Which of the following representations in two's complement notation represents the largest value?

01111111

11111111

00000010 Eftir yfirferð...hitt eru mínustölur og 1, en þetta er 2.

10000000

In two's complement notation, the left-most bit determines the sign of the number. '00000010' represents the largest positive value as it is a positive number with all other bits being zeros.

Explanation

In two's complement notation, the left-most bit determines the sign of the number. '00000010' represents the largest positive value as it is a positive number with all other bits being zeros.

10. Which of the following Boolean operations produces the output 1 for the fewest number of input patterns?

NAND

AND

OR

XOR

The correct answer is AND because in order for the AND operation to produce an output of 1, all the input patterns must be 1. For OR, only one input pattern needs to be 1. NAND produces 0 only when both inputs are 1. XOR produces 1 when the inputs are different.

Explanation

The correct answer is AND because in order for the AND operation to produce an output of 1, all the input patterns must be 1. For OR, only one input pattern needs to be 1. NAND produces 0 only when both inputs are 1. XOR produces 1 when the inputs are different.

11. What is the result of the following addition problem(using two's compliment notation): 00001111 + 10101010?

00011011

11000101

10111001

01110111

The correct way to add two numbers in two's complement notation is to perform binary addition and discard any overflow. In this case, 00001111 + 10101010 = 10111001.

Explanation

The correct way to add two numbers in two's complement notation is to perform binary addition and discard any overflow. In this case, 00001111 + 10101010 = 10111001.

12. Which of the following systems is least efficient when encoding numeric values?

Excess-3 code

Gray code

ASCII

Binary-coded decimal (BCD)

ASCII is a character encoding standard that often requires multiple bytes to represent a single numeric value, making it less efficient than the other encoding systems for numeric values.

Explanation

ASCII is a character encoding standard that often requires multiple bytes to represent a single numeric value, making it less efficient than the other encoding systems for numeric values.