A Level Computer Science OCR Practice Exam

What is the binary system characterized by?

1. A numerical system that uses 10 digits

2. A numerical system that uses only 0 and 1

3. A system that only represents negative numbers

4. A system for complex calculations

The correct answer is: A numerical system that uses only 0 and 1

The binary system is characterized by its use of only two digits: 0 and 1. This simplicity is foundational to digital computing, where all data and instructions are ultimately represented in binary form. Each binary digit, or bit, can be either a 0 or a 1, which allows for the representation of all types of data, from numbers to letters to complex instructions, through combinations of these two values. In digital circuits, binary signals correspond to the two states of electrical voltage: the absence of voltage can represent a 0, while the presence of voltage can represent a 1. This clear representation makes the binary system essential for computer architecture, programming, and data processing, enabling efficient and reliable computation and storage. Other choices describe characteristics unrelated to the binary system itself. The first option mentions a numerical system that uses 10 digits, which refers to the decimal system. The third option talks about representing only negative numbers, which does not capture the breadth of what the binary system can represent, as it can represent both positive and negative numbers depending on the notation used, such as two's complement. The fourth option implies a system for complex calculations, which is a broad description that can apply to various numerical systems, including but not limited to binary