Question Discussion & Solution

The pattern is as follows:

The first letter in each group is a series of vowels in reverse alphabetical order.

The second letter in each group is the opposite letter to the first one.

Hence, “AZ” is the correct answer.

The correct answer is Harmeet Desai.

• Harmeet Desai won the men's singles title at the International Table Tennis Federation Challenge Indonesia Open 2019 Table Tennis Tournament.

Key Points

• The tournament was held in Batam, Indonesia. 
• He also won the Commonwealth championship in July 2019 held in Cuttack, Odisha. 
• He defeated Amalraj Anthony of India.

Additional Information

• Table Tennis:
  • The first match of The Table Tennis World Championship was played in 1927.
  • Table Tennis Association of India was formed in 1938.
  • Terminologies used in Table Tennis are Volley, Late service, Half volley, Backhand, Drive spin, Topspin, Chop, etc.
  • Swaythling Cup, Corbitton Cup, Barna-Bellack Cup, and Ramanujan Trophy are related to table tennis.

 CONCEPT:

• Electromagnetic waves or EM waves (Lightwave): The waves that are formed as a result of vibrations between an electric field and a magnetic field and they are perpendicular to each other and to the direction of the wave is called an electromagnetic wave.
• The accelerating charged particle produces an electromagnetic (EM) wave.
• A charged particle oscillating about an equilibrium position is an accelerating charged particle.
• Electromagnetic waves do not require any matter to propagate from one place to another as it consists of photons.
• Hence they can move in a vacuum 

Properties of Lightwaves:

• Not have any charge or we can say that they are neutral.
• Propagate as a transverse wave with both wave and particle nature.
• They move with the velocity the same as that of light i.e 3 × 108 m/s.
• It contains energy and they also contain momentum.
• They can travel in a vacuum also and always travel in a straight line.

EXPLANATION:

• All of the above-given statements are true.
• Light travels in a straight line until its path is obstructed.
• Light has dual nature, that is, it shows both waves as well as particle nature.
• Light is a transverse wave as the particles of lightwave vibrate in a direction perpendicular to the direction of propagation.

The correct answer is SRAM.

​Key Points

• SRAM memory devices are very much similar, mainly in terms of speed, to the cache memory.
• SRAM stands for Static random-access memory.
• Static random-access memory is a type of random-access memory that uses latching circuitry to store each bit.
• SRAM is volatile memory; data is lost when power is removed.
• The term static differentiates SRAM from DRAM which must be periodically refreshed.

Additional Information

• Dynamic random access memory (DRAM) is a type of semiconductor memory that is typically used for the data or program code needed by a computer processor to function.
• Flash memory, also known as flash storage, is a type of nonvolatile memory that erases data in units called blocks and rewrites data at the byte level.
• EEPROM (electrically erasable programmable read-only memory) is user-modifiable read-only memory (ROM) that can be erased and reprogrammed (written to) repeatedly through the application of higher than normal electrical voltage.

The correct answer is Soap solution is alkaline.

Concept:

• Indicators are the substances that are used to identify whether the given substance is an acid or a base.
• There are two types of indicators:
  • Natural: These indicators are obtained from natural sources like plants. 
  • Turmeric, litmus, china rose petals, etc., are some of the naturally occurring indicators.
  • The most commonly used natural indicator is litmus.
  • It is extracted from lichens.
  • It is available in the form of a solution, or in the form of strips of paper, known as litmus paper.
  • Generally, it is available as red and blue litmus paper.
  • Man-made: Phenolphthalein, Methyl orange are some of the man-made indicators.

Explanation:

• • The indicators change their colour when added to a solution containing an acidic or a basic substance.
  • Turmeric is a natural indicator. It contains the substance

curcumin which changes colour with pH.

• When a substance is basic, the colour is red, whereas when the substance is acidic, the colour of turmeric turns yellow to brown

• Turmeric stains on the shirt turn red when washed with soap because the soap solution is basic in nature which changes the yellow colour of Turmeric into red colour.
• It is because turmeric contains tartaric acid, while the soap contains a sodium hydroxide base. When an acid reacts with a base, a neutralization reaction takes place and the stain becomes neutral.

Neutralization Reaction

• A neutralization reaction can be defined as a chemical reaction in which an acid and base quantitatively react together to form salt and water as products.

Saponification

• Saponification is the hydrolysis of an ester with NaOH or KOH to give alcohol and sodium or potassium salt of the acid.