Question Discussion & Solution

The correct answer is Dial-up.

Key Points

• Dial-up Internet access is a form of Internet access that uses the facilities of the public switched telephone network (PSTN) to establish a connection to an Internet service provider (ISP) by dialling a telephone number on a conventional telephone line.
• Dial-up connections use modems to decode audio signals into data to send to a router or computer and to encode signals from the latter two devices to send to another modem. 
• It is considered the slowest internet service among all.

Additional Information

• In 1979, Tom Truscott and Steve Bellovin, graduates of Duke University, created an early predecessor to dial-up Internet access called the USENET. 
• 5G can be significantly faster than 4G, delivering up to 20 Gigabits-per-second (Gbps) peak data rates and 100+ Megabits-per-second (Mbps) average data rates.
• 5G is considered the fastest internet service till now.

The correct answer is 4°C.

• Freezing of Water:
  • As water freezes, cold water (or ice formed) comes on the surface and warm water goes down.
  • Since the freezing temperature of the water is 0ºC or 273 K.
  • So water at the bottom should be at a higher temperature.
  • Water density at 4ºC is more than the density of water at 0ºC, hence the correct option is 4ºC.

​Key Points

• Reason of low temperature at bottom of the top layer:
  • This is due to the process of convection.
  • When the temperature of the water at the top layer reaches the freezing point, it is converted to ice.
  • But ice is lighter than water, so it will not sink to the bottom.
  • So there will be ice on the top surface and water would remain at the bottom of the lake. 

​The correct answer is Sirohi.

• The district of Rajasthan, where the tropical dry deciduous forests are not found in Sirohi.

Key Points

• Biodiversity of Rajasthan:
  • Though a large percentage of the total area is desert and even though there is little forest cover, Rajasthan has rich and varied flora and fauna.
  • The natural vegetation is classed as Northern Desert Thorn Forest (Champion 1936).
  • These occur in small clumps scattered in more or less open forms.
  • The density and size of patches increase from west to east following the increase in rainfall.
  • The Northwestern thorn scrub forests lie in a band around the Thar Desert, between the desert and the Aravallis.
  • The Aravalli and the south-eastern region is home to the dry deciduous forests, with tropical dry broadleaf forests that include teak, Acacia, and other trees. Hence Sirohi is the correct answer.
  • The hilly ‘Vagad’ region lies in southernmost Rajasthan.
  • Vagad is the wettest region in Rajasthan, and the most heavily forested.
  • North of ‘Vagad’ lies the Mewar region, home to the cities of Udaipur and Chittaurgarh.
  • All these regions have varied flora and fauna distinct to the region.

Additional Information 

• Plant Biodiversity:
  •  Red data Species - 02
  • Orchids - 14
  • Terrestrial - 08
  • Epiphytic - 06
  • Parasitic Species -10
  • Carnivorous Species - 05
  • Endemic Species -19
  • Medicinal Plant Species -157+ 

The correct answer is Concave lens.

Key Points

• To treat the eye disease known as myopia or nearsightedness we use the Concave Lens.
• A concave lens is a category of lens that deviates a straight light beam coming from the origin to a diminished, upright, virtual image.
• It can construct both real and virtual images.
• The convex lens is a lens that tends to meet at a point of rays of light that convey parallel to its principal axis which is comparatively thick across the middle and thin at the lower and upper edges.
• A convex lens is used in cameras, correction of Hyperopia, etc.
• Bifocal lenses hold two different prescriptions, an upper part to allow for distance vision and an additional power on the bottom part of the lens to help in close-up focus.
• A bifocal lens is used in people suffering from presbyopia, myopia, hyperopia, and astigmatism.
• The result is eyesight lucidity at both distance and near with one pair of glasses.
• A Compound lens is simple lenses made on a general axis usually in close proximity and often cemented with each other.

Additional Information

1^st letter: increase by - 8, - 4, - 2, - 1

P - 8→ H - 4→ D - 2 → B - 1 → A

2^nd letter: second letter increase by + 2

K + 2→ M +2 → O + 2 → Q + 2 → S

3^rd letter: Decrease by - 1

R - 1→ Q – 1 → P - 1 → O – 1 → N