Question Discussion & Solution

The correct answer is CPU.

Key Points

• CPU (Central Processing Unit) -
  • It is the main part of the computer, it can also be called the 'brain of the computer'.
  • Its function is to process the inputs and instructions coming on the computer. 
  • This unit of computer performs arithmetic, logical, control functions, input functions, and output functions. 
  • It is also commonly known as a processor.

Additional Information

• Motherboard -
  • It is a printed circuit board installed in most electronic plants such as laptops, computers, etc.
  • It is also called the mainboard or system board.
  • The main part of the motherboard is its chipset.
• RAM (Random Access Memory) -
  • This is a type of memory, we also know it by the name of Primary Memory.
  • There are two types of RAM. Static RAM and Dynamic RAM

Input Devices:

• Input devices are the component of the computer system that accepts incoming data and instructions.
• It converts them into a pattern of electrical signals in binary code that is understandable to a digital computer.

Output Devices:

• Output devices are the component of a computer system that converts the digitized signals into a form understandable to the user.
• The output devices are generally known as the reverse of input devices.
• Output devices also send data from one computer system to another.

Key Points

•  A Visual Display Unit (VDU) is also referred to as a Monitor and VDU (video display unit), a monitor is an output device that displays video images and text.
• A printer is an external hardware output device that takes the electronic data stored on a computer or other device and generates a hard copy.
• A floppy disk is a type of disk storage composed of a disk of thin and flexible magnetic storage medium, sealed in a rectangular plastic enclosure lined with fabric that removes dust particles. It can be both an input and output device.​

Important Points

The Central Processing Unit (CPU):

• The CPU is the brain of the computer.
• Sometimes referred to simply as the processor or central processor, the CPU is where most calculations take place.
• The CPU executes the programs and controls the operation of all the hardware.
• A central processing unit (CPU), also called a central processor, main processor, or just processor is the electronic circuitry that executes instructions comprising a computer program.
• The CPU performs basic arithmetic, logic, controlling, and input/output (I/O) operations specified by the instructions in the program.

​Thus, CPU is not a computer output device.

Mistake Points

• The question is "Which one is not a computer output device?"
• Floppy is both input and output.
• CPU is the only option that is not an output device.

Additional Information

The basic difference between Input and Output devices:

Five friends: A, C, F, U and Z.

1) F is shorter than A who is shorter than Z.

F < A < Z

2) C is shorter than F but not as shorter as U.

This means U is shorter than C.

U < C < F

Combining 1) and 2), we get:

U < C < F < A < Z

The pattern is as follows:

The first letter in each group is a series of vowels in reverse alphabetical order.

The second letter in each group is the opposite letter to the first one.

Hence, “AZ” is the correct answer.

CONCEPT:

Nuclear reactor:

• It is a device in which a nuclear reaction is initiated, maintained, and controlled.
• It works on the principle of controlled chain reaction and provides energy at a constant rate.

EXPLANATION:

• Nuclear Fuel: It is a fissionable material to be used for the fission process to take place. Therefore option 1 is correct.
• Commonly used fuels in a nuclear reactor are U233, Enriched U235, Pu239 etc. 
• Generally, uranium oxide pellets are inserted end to end into long hollow metal tubes constituting the fuel rods.
• When slow neutrons interact with the fuel, the fission starts, and the energy is released. 

Additional Information

• The moderator's function is to slow down the fast-moving secondary neutrons produced during the fission.
  • The material of the moderator should be light and it should not absorb neutrons.
  • Usually, heavy water, graphite, deuterium, and paraffin, etc. can act as moderators.
• Controller: These are made with neutron-absorbing material such as cadmium, hafnium or boron, and are inserted or withdrawn from the core to control the rate of reaction, or to halt it. 
• Lubricant: Lubricant has shown that it is possible to produce materials capable of lubricating some reactor components.
  • In order to further the development of such lubricants, the U.K.A.E.A. and the nuclear manufacturing groups have co-operated in providing lubricant manufacturers.