Question Discussion & Solution

The correct answer is Hygrometer.

Key Points

• Hygrometer
  • A hygrometer is an instrument for measuring the relative humidity of the atmosphere.
  • The hygrometer was invented by Leonardo da Vinci.

Additional Information

• ​Barometer
  • A barometer is an instrument used to measure atmospheric pressure.
  • The barometer was invented by Torricelli.
• Hydrometer
  • A hydrometer is an instrument used to measure the specific gravity of liquids.
  • The hydrometer was invented by Nicholson.
• ​Anemometer
  • An anemometer is an instrument used to measure the velocity of wind and directions.
  • The anemometer was invented by Leon Alberti.

The relation among the given numbers is:

1 × 2 = 2

2 % 3 = 2

2 × 4 = 8

8 % 5 = 3

3 × 6 = 18

18 % 7 = 4

4 × 8 = 32

32 % 9 = 5

(where ‘%’ is the modulo or the remainder operator.)

The correct answer is chemical energy.

Key Points

• The dry cell is a type of electric battery which is used for portable electrical devices.
• Electricity is produced through the dry cells from electrochemical energy. Hence, Option 1 is correct.
• A common dry cell is a zinc-carbon cell.
• The electrolyte is immobilized as a paste by a dry cell, with just enough humidity in it to allow current to flow.
• Like a wet cell, a dry cell can work without spilling in any direction, because there is no free liquid in it.
• The versatility makes it ideal for mobile devices.
• The first wet-cell batteries, in comparison, were usually fragile glass containers featuring lead rods sticking from an open-top.
• Hence, they required careful handling to prevent spillage.
• The dry-cell battery development made a significant advance in battery safety and portability.
• Batteries render electricity from chemical energy.
• Batteries consist of one or more different parts, or cells, which contain an electrolyte called a chemical.
• Every cell has two electrodes that are electrically conductive immersed in its electrolyte.
• The electrodes consist of different materials; one releases electrons into the electrolyte, and the other absorbs them.
• Once an electrical system is attached to the electrodes, an electrical current passes through it and supports its operation with electric power.
• The energy contained in the dry cell is therefore in the form of chemical energy.

Additional Information

• Thermal energy
  • It is also called heat energy 
  • It is produced when a rise in temperature causes atoms and molecules to move faster and collide with each other.
  • The energy that comes from the temperature of the heated substance is called thermal energy.
  • Thermal energy is energy that comes from a substance whose molecules and atoms are vibrating faster due to a temperature rise.
• In physical sciences, mechanical energy
  • It is the sum of potential energy and kinetic energy.
  • It is the macroscopic energy associated with a system.
  • The principle of conservation of mechanical energy states that if an isolated system is subject only to conservative forces, then the mechanical energy is constant.
• Nuclear power
  • It is the use of nuclear reactions to produce electricity.
  • Nuclear power can be obtained from nuclear fission, nuclear decay, and nuclear fusion reactions.
  • Presently, the vast majority of electricity from nuclear power is produced by nuclear fission of uranium and plutonium in nuclear power plants.

The logic followed here is:-

The first two words are antonyms of each other.

'Always' is antonym of 'Never'.

Similarly,

The fourth word should be the antonym of the third word.

'Down' is antonym of 'Up'.

So, Never : Always :: Up : Down.

Hence, the correct answer is "Down".

The correct answer is ​Wide Area Network (WAN).

Key Points

• A global system of interconnected computers, using a standardized Internet Protocol suite for communication and sharing information is called the Internet.
• World Wide Web or ‘www’ is a collection of web pages that can easily be published on the Internet and read by millions of its users. 
• The first development was the introduction of host-to-host network interactions.
• This was first observed in ARPANET in 1969.
• It was developed by the Advanced Research Projects Agency (APRA) of the Department of Defence, U.S. It was one of the first general usages of computer networks.

Important Points

• A personal area network, or PAN, is a computer network organized around an individual person within a single building. This could be inside a small office or residence.
• A typical PAN would include one or more computers, telephones, peripheral devices, video game consoles, and other personal entertainment devices.
• A local area network, or LAN, consists of a computer network at a single site, typically an individual office building. A LAN is very useful for sharing resources, such as data storage and printers.
• LANs can be built with relatively inexpensive hardware, such as hubs, network adapters, and Ethernet cables.
• A metropolitan area network, or MAN, consists of a computer network across an entire city, college campus, or small region. A MAN is larger than a LAN, which is typically limited to a single building or site.
• Depending on the configuration, this type of network can cover an area from several miles to tens of miles. A MAN is often used to connect several LANs together to form a bigger network.
• When this type of network is specifically designed for a college campus, it is sometimes referred to as a campus area network, or CAN.
• A wide area network, or WAN, occupies a very large area, such as an entire country or the entire world. A WAN can contain multiple smaller networks, such as LANs or MANs. The Internet is the best-known example of a public WAN.