Question Discussion & Solution

The correct answer is Operating system.

Key Points

• UBUNTU is an example of an operating system.
• The operating system is a collection of programs that controls the overall operations of the computer.
• Operating systems are of two types namely, Open-source operating systems and Closed source operating systems.
• UBUNTU is free and open-source software.
• Operating systems works as an interface between a user and computer hardware components.
• Examples of operating systems are:
  • Linux
  • Unix
  • DOS
  • Windows
  • Ubuntu
  • Embedded operating system
  • OpenBSD
  • Mac OS

Additional Information

• Malware is a file or code that is designed to damage and destroy computers and computer systems.
  • Viruses, worms, Trojan viruses, spyware are the common examples of malware.
• A web browser is an application used to access and view websites.
  • Google Chrome, Mozilla Firefox, Apple Safari are the common examples of web browsers.

The correct answer is Vitamin A.

• Vitamin A causes Night Blindness.

Key Points

• Night blindness is a type of vision impairment also known as nyctalopia. People with night blindness experience poor vision at night.
• Vitamin was first invented by FG Hopkins.  However, the term vitamin was coined by C Funk. 
• Good sources of vitamin A include cheese, eggs oily fish.

Additional Information

• Vitamin B₁₂ deficiency may lead to a reduction in healthy red blood cells (anaemia). 
• Vitamin C is found in citrus fruits and vegetables.
  • Scurvy results from a deficiency of vitamin C in the diet.
• The signs and symptoms of vitamin D deficiency include Fatigue, Bone pain, muscle weakness, muscle aches, or muscle cramps.
  • Rickets is caused due to deficiency of vitamin D
• Vitamin E deficiency can cause nerve and muscle damage loss of body movement control, muscle weakness, and vision problems.

For alphabet: Increase by + 4

 D + 4 → H + 4 → L + 4 → P + 4 → T + 4 → X

For Number: Decrease number by - 4

23 – 4 → 19 – 4 → 15 – 4 → 11 – 4 → 7 – 4 → 3

Total number of boxes of matchsticks = 3600

Total number of cartons = 10

Let the number of packets in one carton be x.

⇒ Number of packets in 10 cartons = 10x.

Number of boxes of matchstick in a packet = 30

⇒ Number of boxes of matchstick in 10x packets = 30(10x) = 300x

So, we have:

Total number of boxes = Number of boxes of matchstick in 10x packets

⇒ 300x = 3600

⇒ x = 12

The correct answer is 240 J.

Key Points

• When a force is applied to an object which causes displacement along the direction of force then the work is said to be done by that force.
• The work done by a force is defined as "the product of the component of the applied force on the block in the direction of the displacement and the magnitude of this displacement" is called work done.

Additional Information

• i.e., \(W = \vec F.d\vec x = Fdx\cos \theta \)

or in terms of magnitude, it can be given as

\(W\; = \;F \times s\)

• Here both force and displacement will be along the same direction since force is causing this displacement thus Work done is a scalar quantity.
  • Here,
  • Force applied on object = F
  • Displacement of object = dx
  • Distance traveled by an object = s
  • The angle between Force and displacement = θ
• Calculation:
  • Given that,
  • Person raised the box of weight 120 N through the height of 2 m
  • i.e., F = 120 N 
  • x = 2 m
• Thus from the above explanation, we can see that
• Work = Force × Distance moved in the direction of the force
• Force of 120 N is acting downwards, Therefore
  • Work Done = 120 × 2 = 240 J