Question Discussion & Solution

The correct answer is Butane.

Key Points 

• Liquefied Petroleum Gas (LPG) is a blend of light hydrocarbon compounds.
  • It mainly consists of butane or propane or a mixture of both.
  • At room temperature, both gases are colourless and odourless.
  • It is a mixture of 48% propane, 50% butane, and 2% pentane.

Additional Information

• Water Gas:
  • Water-gas is a mixture of CO and H₂.
  • However, by-products such as char, tar, soot, ash, and condensates are also produced. 
• Natural gas is a naturally occurring hydrocarbon gas mixture consisting primarily of methane, but commonly including varying amounts of other higher alkanes, and sometimes a small percentage of carbon dioxide, nitrogen, hydrogen sulfide, or helium.
• Compressed natural gas is a fuel that can be used in place of petrol (gasoline), diesel fuel, and liquefied petroleum gas (LPG).
  • CNG combustion produces fewer undesirable gases than the aforementioned fuels.
  • In comparison to other fuels, natural gas poses less of a threat in the event of a spill, because it is lighter than air and disperses quickly when released.

Data for B+ Tree:

Disk Block size = D= 256 byte

Block pointer = B = 2 byte

Key field = K = 8 byte.

Order = p

Formula:

p × 2 + (p – 1) (8) ≤ 256

Calculation:

p × 2 + (p – 1) (8) ≤ 256

2p + 8p ≤ 264

p ≤ 26.4

∴ p = 26

Rajasthani folk art has been divided into the following types:

• Wall & ground paintings: Devra, Pathwari, Sanjhi , Mandav etc.
• Cloth Paintings: Pat, Pichhwai, Phad etc.
• Painting on Paper: Paane
• Painting made on wood: Kavad
• Painting on Human Body: Mehendi, Godana

Additional Information

Phad painting is a folk painting, practiced in Rajasthan. Traditionally, this painting is done on a long piece of cloth or canvas, known as phad. Examples of this art are Devnarayan Ki Phad and Pabuji Ki Phad.

The correct answer is Leeuwenhoek.

Key Points

Additional Information

• Penicillin:
  • Penicillin is one of the first and still one of the most widely used antibiotic agents, derived from the Penicillium mold.
  • In 1928 Scottish bacteriologist Alexander Fleming first observed that colonies of the bacterium Staphylococcus aureus failed to grow in those areas of a culture that had been accidentally contaminated by the green mold Penicillium notatum.
  • He isolated the mold, grew it in a fluid medium, and found that it produced a substance capable of killing many of the common bacteria that infect humans.
  • Australian pathologist Howard Florey and British biochemist Ernst Boris Chain isolated and purified penicillin in the late 1930s, and by 1941 an injectable form of the drug was available for therapeutic use.
• Microscope:
  • Microscope is an instrument that produces enlarged images of small objects, allowing the observer an exceedingly close view of minute structures at a scale convenient for examination and analysis.
  • Although optical microscopes are the subject of this article, an image may also be enlarged by many other waveforms, including acoustic, X-ray, or electron beam, and be received by direct or digital imaging or by a combination of these methods.
  • The microscope may provide a dynamic image (as with conventional optical instruments) or one that is static (as with conventional scanning electron microscopes).
• Reverse transcriptase:
  • Reverse transcriptase also called RNA-directed DNA polymerase, an enzyme encoded from the genetic material of retroviruses that catalyzes the transcription of retrovirus RNA (ribonucleic acid) into DNA (deoxyribonucleic acid).
  • This catalyzed transcription is the reverse process of normal cellular transcription of DNA into RNA, hence the names reverse transcriptase and retrovirus.
  • Reverse transcriptase is central to the infectious nature of retroviruses, several of which cause disease in humans, including human immunodeficiency virus (HIV), which causes acquired immunodeficiency syndrome (AIDS), and human T-cell lymphotropic virus I (HTLV-I), which causes leukemia.
• Bacteria:
  • Bacteria, singular bacterium, any of a group of microscopic single-celled organisms that live in enormous numbers in almost every environment on Earth, from deep-sea vents to deep below Earth’s surface to the digestive tracts of humans.
  • Bacteria lack a membrane-bound nucleus and other internal structures and are therefore ranked among the unicellular life-forms called prokaryotes.
  • Prokaryotes are the dominant living creatures on Earth, having been present for perhaps three-quarters of Earth history and having adapted to almost all available ecological habitats.
  • As a group, they display exceedingly diverse metabolic capabilities and can use almost any organic compound, and some inorganic compounds, as a food source.

The correct answer is option 3.

Concept:

A semaphore is a variable or abstract data type used to control access to a common resource by multiple threads and avoid critical section problems in a concurrent system such as a multitasking operating system.

Explanation:

Starvation is a problem that happens when high-priority processes continue to run while low priority processes are halted indefinitely. A continual stream of higher-priority processes in a densely loaded computer system can prevent a low-priority operation from ever receiving the CPU.

Indefinite blocking or starvation is a situation in which processes wait indefinitely within the semaphore. Indefinite blocking may occur if we remove processes from the list associated with a semaphore in LIFO (last-in, first-out) order.

Hence the correct answer is starvation.

Additional InformationCritical section:

 The critical section is the section of code in which processes access and write to shared resources such as common variables and files. Because processes run continuously, any process can be interrupted in the middle of its execution.