Question Discussion & Solution

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.

Oboe is a musical instrument. Similarly, scalpel is a surgical instrument used in surgeries.

The correct answer is the Graphical User Interface.

Important Points

• Graphical User Interface (GUI) 
  • The graphical user interface is used by most of the commercially popular computer operating systems.
  • A Graphical User Interface (GUI) allows you to enter commands by pointing and clicking at objects that appear on the screen.
  • It consists of picture-like items (eg. icons and arrows).
  • In most operating systems, the primary user interface is graphical.

Key Points

• Some popular, modern graphical user interface examples include:
  • Microsoft Windows,
  • macOS, Ubuntu Unity,
  • GNOME Shell for desktop environments, and
  • Android,
  • Apple's iOS,
  • BlackBerry OS,
  • Windows 10 Mobile,
  • Palm OS-WebOS, and
  • Firefox OS for smartphones.​

Explanation:

• One of the most important contributors to the early construction of the periodic table was Russian scientist Dmitri Ivanovich Mendeléev.
• Mendeleev Periodic Table was introduced in 1869, following the rejection of Newlands Octave Law.
• Elements were arranged in Mendeleev's periodic chart according to their fundamental property, atomic mass, and chemical characteristics.
• Only 63 elements were known at Mendeleev's time.
• Mendeleev discovered that the properties of elements are the periodic function of their atomic mass in a periodic pattern after analysing their qualities.
• He ordered the elements in the periodic table so that those with comparable properties were in the same vertical columns.
• He developed a periodic law based on this finding, which states:- “The periodic function of an element's atomic mass is its property.”
• Demerits -  
  1. He couldn't find hydrogen in the periodic chart.
  2. Moving from one element to the next caused an irregular increase in atomic mass. As a result, the amount of elements that have yet to be identified is unpredictable.
  3. Isotopes were not considered. Later on, isotopes of elements that defied Mendeleev's periodic law were discovered.​ 

Additional Information

Mendeleev left places for undiscovered elements. 

• scandium, gallium and germanium, discovered later, have properties similar to Eka–boron, Eka–aluminium and Eka–silicon, respectively. So undiscovered elements were named also by Mendeleevs. 
• It was not very strictly based on increasing order of atomic mass.  For example, cobalt (atomic mass 58.9) appeared before nickel (atomic mass 58.7) based on periodic properties. 
• Noble gases can easily get adjusted in Mendeleev periodic table even they were discovered after the periodic table. 

The correct answer is Article 167.

• Article 167 of the Indian Constitution defines the duties of the Chief Minister.
• It has specified in the second schedule.
• A chief minister is understood to be "first among equals".

A Chief Minister must be:

• Chief Minister must be a citizen of India.
• Chief Minister should be a member of the state legislature.
• If a person is elected chief minister who is not a member of the legislature, then he/she must take permission from the governor.
• Chief Minister must be 25 years of age or more.