Question Discussion & Solution

Valency is the combining power of an element. Elements in the same group of the periodic table have the same valency.

Key Points

• Valency is the no of electron that looses, shared or gain to achieve stability or we can say to complete it outer most shell. 
• If any element has valence electron (electrons present in outer most shell) less than 4
  • ​​Valency = no of valance electron (valence electron<4)
• If any element has valence electron ​more than 4
  • ​​Valency = 8 - no of valance electron (valence electron>4)

​For Lithium:

• Li(Z=3) Electronic configuration = 2, 1
  • Valency = no of valance electron  = 1

​Hence, we can conclude that 1 is the valency of Lithium.

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The correct answer is All of these

• An operating system (OS) is system software that manages computer hardware and software resources and provides common services for computer programs.
• The three most common operating systems for personal computers are Microsoft Windows, Mac OS X, and Linux.
• Modern operating systems use a graphical user interface(GUI).
• An Operating System (OS) is an interface between a computer user and computer hardware. An operating system is a software that performs all the basic tasks like file management, memory management, process management, handling input and output, and controlling peripheral devices such as disk drives and printers.
• Some popular Operating Systems include Linux Operating System, Windows Operating System, VMS, OS/400, AIX, z/OS, etc.
• The following are some of the important functions of an operating system:
  • Memory Management
  • Processor Management
  • Device Management
  • File Management
  • Security
  • Control over system performance
  • Job accounting
  • Error detecting aids
  • Coordination between other software and users

The correct answer is Red Light.

Concept:

Photosynthesis: 

• The leaves have a green pigment called chlorophyll.
• It helps leaves to capture the energy of the sunlight.
• This energy is used to synthesise (prepare) food from carbon dioxide and water. Since the synthesis of food occurs in the presence of sunlight, it is called photosynthesis.

In the presence of sunlight Carbon dioxide + water → Carbohydrate + oxygen.

• Some plants, green algae, and cyanobacteria can perform photosynthesis.
• The process of photosynthesis is commonly written as

                   6CO2 + 6H2O + Sun-Light → C6H12O6 + 6O2

Explanation:

• Photosynthesis is maximum in the Red colour of Light and Least in the Green colour of Light.
• In the absorption spectrum, the red & blue lights are absorbed while the majority of green light gets reflected
• Photosynthesis range from 400 to 700 nm, It absorbs the Violet, Blue and Red colour of Light.

The correct option is Most of the bees in the hive are worker bees.

• Every honey bee colony comprises a single queen, a few hundred drones and several thousand worker castes of honey bees.
• A queen bee is the only female bee in the hive that gets to reproduce.
• Worker bees are all female and are all offspring of the queen. 
• Queen is a fertile, functional female, the worker is a sterile female and the drone is a male insect.
• Queen and worker develop from the fertilized egg while drone develops from an unfertilized egg.
• Further differentiation of queen and worker depends on the quality and quantity of food that is fed to the queen or worker larvae.

Explanation:

​Every beehive has one male bee and many female bees → Inorrect.

Most of the bees in the hive are worker bees → Correct

The study of honey bee is sericulture → Inorrect.

Beehives are octagonal in shapes→ Incorrect. (Hexagonal)

​Additional Information

The queen:

• ​There is only one queen in a colony and considerably larger than the members of other castes.
• Swarming is the natural method that honeybee colonies use for multiplying their colonies.
• The old queen is killed as soon as the new queen is fertilized.
• The phenomenon of raising a queen in the off-season is called supersedure.
• The normal lifespan of a queen is 3 years.

​The drone:

• ​The drones are male bees with no sting.
• They are much larger and stouter than either the queen or the workers.
• Their only function is to impregnate the young queen a task which they are unable to perform until they are about 10 days of age.
• They also help in the maintenance of hive temperature. 
• The drones are produced by unfertilized eggs of the queen, or by those workers which take up the reproductive function due to the absence of a queen in a colony.
• The normal lifespan of a drone is 57 days. 

​The worker:

• ​Smallest inhabitants of the beehive.
• They are imperfect females incapable of laying eggs.
• Worker bees primary duties are cleaning, feeding developing larva once hypopharyngeal glands develop, ripening of honey, secreting/moulding of wax into combs.
• The lifespan of a worker is about 4 weeks during the active season and 8 to 10 weeks during the less active season.
• On certain occasions when the colony is in need of a queen, some of the workers start laying eggs from which only drones are produced.
• These workers called laying workers.