Question Discussion & Solution

• Direct memory access (DMA) is a feature of computer systems that allows certain hardware subsystems to access main system memory (RAM), independent of the central processing unit (CPU)
• Disk drive is a hardware subsystem

The correct answer is option 2.

Concept:

A process control block (PCB) is a data structure used by computer operating systems to store all process-related information. A process descriptor is another name for it. The operating system creates a process control block when a process is created (initialized or installed).

Process Control is a set of system calls that perform tasks such as process creation, termination, and so on.

Process Control Functions:

• End and Abort
• Load and Execute
• Abort, end
• Create Process and Terminate Process
• Wait and Signal Event
• Allocate and free memory.

Hence the correct answer is process control.

Additional Information File Management:

File manipulation tasks such as creating, reading, and writing is handled by file management system calls.

File manipulation Functions:

• Create a file
• Delete file
• Open and close file
• Read, write, and reposition
• Get and set file attributes

Device Management:

Device management is responsible for device manipulation such as reading from and writing to devise buffers.

Device management Functions:

• Request and release device
• Logically attach/ detach devices
• Get and Set device attributes

Information Maintenance:

It handles information and its transfer between the OS and the user program.

Information Maintenance Functions:

• Get or set time and date
• Get process and device attributes

The Correct Answer is Option (2) i.e Pancreas.

Key Points

• In humans, the kidney is one of the main organs of the excretory system.
• The kidney's function is the filtration of the blood and removing waste(toxic) products.
• Waste products and excess fluid are removed through the urine.
• If the kidney fails person needs to undergo dialysis.
• Dialysis is a treatment that filters and purifies the blood using a machine
• The human excretory system includes certain organs that eliminate the wastes such as salts, carbon dioxide, urea, uric acid and water produced by the body.
• The path of the urine in the human excretory system is -
• After filtering from the kidney → The urine through Ureter → Stored in the Urinary bladder → Exits through the urethra.

Important Points

• The Pancreas is an organ located in the abdomen. It is not a part of the human excretory system.
• The Pancreas plays an important role in converting the food we eat into fuel for the body's cell.
• It helps in the process of digestion. It also regulates blood sugar.
• The body system that removes metabolic wastes from the body is known as the 'Excretory System'.

Eureka:

• Constantan is a Nickel-Copper alloy also known as Eureka.
• It usually consists of 55% copper and 45% nickel.
• Its main feature is the low thermal variation of its resistivity, which is constant over a wide range of temperatures
• Constantan is a Nickel-Copper-based alloy wire that has a high resistivity and is mainly used for thermocouples and electrical resistance heating.
• It has a constant resistivity over a wide range of temperatures.
   

Composition:

• Ni = 45 %
• Cu = 55 %
   

Properties of Eureka:

• Resistivity - 490 µΩ -cm
• Melting point: 1300 ⁰C
• Specific gravity: 8.9 gm /cm³
• Negligible temperature Coefficient
• Easily ductile
• Resistant to atmospheric corrosion
• Can be easily soldered and moulded
   

Application:

• It is used for the measurement of temperature.
• It is used for the formation of thermocouple, along with the wires of other metals such as copper, iron, and chromium.
• It is especially used for resistance purposes since its resistance does not change much with the change in its temperature. It is used for DC current shunts. 

The correct answer is option 3 i.e. the Atomic Number

• The periodic table is based on Atomic Number.
• The atomic number is the number of protons found in the nucleus of every atom of that element. 
• The periodic table is managed by the International Union of Pure and Applied Chemistry, or IUPAC.
• In 1869, Dimitri Mendeleev included 63 known elements arranged according to increasing atomic weight. But there were many elements he could not place in the periodic table and with the discovery of new noble elements, there was a need to arrange the elements. Henry Moseley later arranged the elements in the periodic table by their number of protons rather than their atomic weights.
• The modern periodic table orders the elements according to increasing atomic number rather than increasing atomic weight.
• There are 118 elements in a periodic table. There are seven periods and eighteen groups in the modern periodic table.
• On moving from left to right in a period, the size of atoms(atomic size) decreases.
• On moving from left to right in a period, the metallic character of elements decreases, whereas the non-metallic character increases.
• While going down in a group of the periodic table, the size of atoms increases (or atomic size increases).
• While going down in a group of the periodic table, the metallic character of elements increases.
• Electronegativity and reactivity of non-metals increase along the period and decrease down the group.