Question Discussion & Solution

CONCEPT:​

• Power of Lens: The inverse of the focal length is known as the power of the lens.
  • It shows the bending strength for the light ray of the lens.

\(P = \frac{1}{f}\)

where P is the power of the lens and f is the focal length of the lens.

• The unit of power of a lens is Dioptre when the focal length of the lens is taken in meter (m).
• The focal length of the convex lens (converging) is positive and that of the concave lens (diverging) is negative. 

CALCULATION:

Given that lens is diverging. so focal length is negative.

f = -5 cm = -0.05 m

Power of lens \(P = \frac{1}{f} =\frac{1}{-0.05} = -20 D\)

P = -20 D

So the correct answer is option 2.

The correct answer is Tobacco.

• In 2019, the Medical and Health Department of the Government of Rajasthan was awarded by the World Health Organization for control over Tobacco.

Key Points

• The Medical & Health Department of Rajasthan launched various campaigns against tobacco consumption at places such as schools, colleges, police stations, and government offices during 2018-19.
• As part of the tobacco-free initiatives, 1.13 crore people took a pledge against tobacco consumption at the events held in 1.56 lakh government institutions on January 30 this year, marking Martyrs’ Day.
• The award was received by the  Medical & Health Department's Additional Chief Secretary, Rohit Kumar Singh on behalf of the government

Additional Information

• World Health Organisation:
  • Established in 1948
  • Headquarters: Geneva, Switzerland.

Concept:

Software maintenance:

Any changes done in the software during its execution such as error correction, optimization etc. is software maintenance. Its objective is to preserve the value of software over time.

Explanation:

Types of software maintenance are:

Perfective maintenance: when there are new requirements from user side, then at that time changes made in the software is known as perfective maintenance. It makes the software more enhanced, clean structured, better than previous.

Adaptive maintenance: Changes done in the software environment that includes any work initiated as consequence of moving the software to different hardware or software is known as adaptive maintenance.

Preventive maintenance: It prevent software from future problems.

The correct answer is Ethanol + Methanol​.

• Ethanol + Methanol​ is denatured alcohol.
• Denatured alcohol is ethanol that has additives to make it poisonous, bad-tasting, foul-smelling, or nauseating to discourage its recreational consumption.
• The term denatured alcohol refers to alcohol products adulterated with toxic and/or bad tasting additives (e.g., methanol, benzene, pyridine, castor oil, gasoline, isopropyl alcohol, and acetone), making it unsuitable for human consumption.
• The most common additive used is methanol (5–10%), giving rise to the term methylated spirits. Denatured alcohol is used as a lower-cost solvent or fuel for home-scale or industrial use.

Key Points

• Denatured alcohol is ethanol or grain alcohol that contains additional chemicals called denaturants that make it unfit for human consumption.
• Denatured alcohol is fine for some types of lab work and as an ingredient in certain products, but it's not safe to drink.
• Ethanol is an organic chemical compound. It is simple alcohol with the chemical formula C₂H₆O.
• Its formula can be also written as CH₃−CH₂−OH or C₂H₅OH and is often abbreviated as EtOH.

Additional Information

• Alcohol (ethanol or ethyl alcohol) is the ingredient found in beer, wine, and spirits that causes drunkenness.
• Alcohol is formed when yeast ferments (breaks down without oxygen) the sugars in different food. 

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