Bn Ch 3 Chapter Test

Explanation
An electronic signal refers to a changing electric current that carries information. It is a form of electrical energy that is used to transmit data or convey messages in electronic devices. This can include signals used in telecommunications, audio and video transmission, and digital data transfer. The other options, diode, transistor, and semiconductor, are components or materials commonly used in electronic circuits but do not specifically refer to the changing electric current itself.

Explanation
A digital signal can be represented by a series of numbers. In digital communication, information is encoded as a sequence of discrete values, typically binary digits (0s and 1s). These numbers can represent various types of data, such as audio, video, or text. The digital signal is used to transmit and process information in devices like microprocessors, which are electronic circuits that carry out arithmetic and logical operations. While read-only memory (ROM) is a type of computer memory that stores data permanently, it does not inherently involve representing information as a series of numbers like a digital signal does.

Explanation
Semiconductors are materials that have electrical conductivity between that of conductors and insulators. The conductivity of semiconductors can be controlled by adding impurities, a process known as doping. Doping introduces atoms of different elements into the semiconductor crystal structure, which either donate or accept electrons, creating excess or deficient charge carriers. This alters the conductivity of the semiconductor, allowing it to be used in various electronic devices such as diodes and microprocessors. Therefore, the statement "Electrical conductivity can be controlled by adding impurities" accurately describes the behavior of semiconductors.

Explanation
A diode is a semiconductor device that allows current to flow in only one direction. It acts as a one-way valve for electric current, allowing it to pass through in one direction while blocking it in the opposite direction. This property makes diodes useful in various applications, such as rectification of alternating current into direct current, voltage regulation, and signal demodulation. Transistors, on the other hand, are three-layer semiconductor devices used for amplification and switching purposes. While they can control the flow of current, they do not restrict it to one direction like a diode does. A binary system refers to a system of numerical notation with only two possible digits, typically 0 and 1, and is not directly related to the given statement.

Explanation
A transistor can be used as an electronic switch or as an amplifier. When used as a switch, it can control the flow of current between two terminals, allowing or blocking the passage of electrical signals. This makes it useful in digital circuits where binary signals are used. On the other hand, when used as an amplifier, the transistor can increase the strength of electrical signals, enabling it to amplify weak signals to a higher power level. This property makes transistors essential in audio and radio frequency applications. Therefore, a transistor is the correct answer as it can serve both as a switch and an amplifier.

Explanation
An integrated circuit is a type of electronic signal that contains large numbers of solid-state components and is made from a semiconductor. It is a small electronic device that can perform various functions and is commonly used in computer hardware.

Explanation
The binary system is a number system that uses only two digits, 0 and 1, to represent all numbers and information. It is widely used in computer systems and digital electronics because it can easily be represented using on/off states or voltage levels. The other options, diode, read-only memory, and analog signal, are not directly related to the concept of a number system using two digits.

Explanation
Input devices, output devices, and memory storage devices are all examples of computer hardware. Computer hardware refers to the physical components of a computer system that can be touched and manipulated. Input devices such as keyboards and mice allow users to input data into the computer, while output devices such as monitors and printers display or produce the results of the computer's processing. Memory storage devices, such as hard drives and RAM, store data and instructions for the computer to access. These hardware components work together to enable the functioning of a computer system.

Explanation
A microprocessor is the correct answer because it is a type of Central Processing Unit (CPU). A microprocessor is an integrated circuit that contains the functions of a central processing unit of a computer. It is responsible for executing instructions and performing calculations in a computer system.

Explanation
RAM stands for Random Access Memory, which is a type of temporary memory in a computer system. It is used to store data and instructions that are currently being processed by the CPU. Unlike ROM (Read-Only Memory), RAM is volatile, meaning its contents are lost when the power is turned off. Therefore, RAM is responsible for storing and providing quick access to data that is actively being used by the computer.

Explanation
ROM stands for Read-Only Memory. It is a type of computer memory that retains its data even when the power is turned off. Unlike RAM (Random Access Memory), which is volatile and temporary, ROM is non-volatile and permanent. It contains pre-programmed data that cannot be modified or erased by normal computer operations. ROM is commonly used to store firmware, bootstrap loaders, and other essential system software that needs to be preserved even when the computer is powered off.

Explanation
The given list of instructions for the computer consists of terms such as transistor, diode, software, and hardware. The terms transistor and diode refer to electronic components used in circuitry. However, software is not a physical component but rather a collection of programs and data that instruct the computer on how to perform tasks. Therefore, the correct answer is software as it is the only term that does not represent a physical component.

Explanation
An analog signal is a type of electronic signal that varies smoothly in time. Unlike a digital signal, which is discrete and composed of individual bits, an analog signal is continuous and can take on any value within a given range. This means that an analog signal can represent a wide range of values and can provide more detailed and precise information. In contrast, a digital signal can only represent a finite number of values, making it less accurate for certain applications.

Explanation
A vacuum tube is a type of tube that was used in old televisions instead of semiconductors. It is a device that controls electric current through a vacuum in a sealed glass tube. Vacuum tubes were commonly used in early electronic devices before the invention of solid-state technology. They were used to amplify and control electrical signals. Therefore, the correct answer is vacuum tube.

Explanation
Doping refers to the process of intentionally adding impurities to semiconductors in order to alter their conductivity. By adding specific impurities, the number of free charge carriers in the semiconductor can be increased or decreased, thus changing its conductivity. This technique is widely used in the semiconductor industry to create different types of electronic devices, such as transistors and diodes, which are essential components of integrated computers.

Explanation
A floppy disk is a type of memory that stores computer information magnetically. It was widely used in the past but is no longer in use due to advancements in technology.

Explanation
The instructions to start a computer are usually found in ROM (Read-Only Memory). ROM is a type of computer memory that stores permanent data and instructions that cannot be modified or erased by normal computer operations. It contains the firmware or BIOS (Basic Input/Output System) that is responsible for initializing the computer hardware and loading the operating system. Unlike RAM (Random Access Memory) which is volatile and loses its data when the computer is turned off, ROM retains its data even without power. Therefore, the instructions to start a computer are stored in ROM.

Explanation
A byte is a unit of digital information that consists of 8 bits. Each bit can represent a value of either 1 or 0, which corresponds to an "on" or "off" state. Therefore, a byte is composed of 8 binary digits, allowing it to represent a wide range of values and characters in computer systems.

Explanation
The correct answer is "metalloid" because a semiconductor is a type of material that has properties of both metals and non-metals. It can conduct electricity under certain conditions, but not as well as a metal. This makes it an intermediate between a conductor (metal) and an insulator (non-metal).

Explanation
The correct answer is mouse, keyboard, and scanner. These three devices are all input devices that allow the user to interact with a computer system. The mouse is used to move the cursor on the screen and select objects, the keyboard is used to input text and commands, and the scanner is used to convert physical documents or images into digital files. The other devices listed, such as the monitor, speakers, and printer, are not input devices but rather output devices that display or produce information from the computer.