Explanation

• The filament of an electric bulb is made of Tungsten.
• Because it has a very high melting point (~3422°C).
• It can glow brightly without melting.
• Tungsten provides efficient and long-lasting light in incandescent bulbs.

Last verified on 15-03-2026

Explanation

The correct order of the alimentary canal, also known as the gastrointestinal (GI) tract:

• Mouth: Food enters the mouth, where it's chewed and mixed with saliva.
• Oesophagus: Food passes through the oesophagus, a muscular tube that transports it to the stomach.
• Stomach: The stomach secretes gastric juices to digest proteins and fats.
• Small Intestine: Nutrient absorption occurs in the small intestine, where specialized structures like villi and microvilli increase the surface area.

Last verified on 15-03-2026

Explanation

• First detected: October 2020, India
• WHO designation: Delta variant (Variant of Concern)
• Contagion rate: Higher than original SARS-CoV-2
• Vaccines effective: Pfizer-BioNTech, Moderna, AstraZeneca
• Global spread: Over 100 countries by mid-2021

Last verified on 15-03-2026

Explanation

• Baking soda releases carbon dioxide (CO₂) gas when it reacts with an acid or heat.
• The CO₂ bubbles expand in the batter, making it soft, fluffy, and porous during baking.
• Chemical formula of baking soda: NaHCO₃ (Sodium bicarbonate).

Last verified on 15-03-2026

Explanation

• A true solution is a homogeneous mixture in which the solute is completely dissolved in the solvent at the molecular level. 
• The particles are very small and cannot be seen with the naked eye. 
• True solutions are stable and do not settle down on standing.

Examples of true solutions (homogeneous mixtures):

• Salt in water (NaCl solution)
• Sugar in water
• Vinegar in water
• Alcohol in water
• Copper sulfate in water

Last verified on 15-03-2026

Explanation

• According to Albert Einstein, light travels in the form of photons, which are tiny packets (quanta) of energy.
• This concept was proposed in 1905 while explaining the photoelectric effect.
• Photons behave like particles but also show wave properties.

Last verified on 15-03-2026

Explanation

• Valency is the combining capacity of an atom to form molecules or compounds.
• It depends on the number of electrons an atom can lose, gain, or share to complete its outer shell.

Last verified on 15-03-2026

Explanation

• All plants move Anticlockwise around Sun.
• All plants move anticlockwise around their axis.
• Earth rotates its axis from West to East.

Last verified on 15-03-2026

Explanation

• Fluoride is commonly added to drinking water in small amounts to prevent tooth decay (dental cavities).
• It strengthens tooth enamel and makes teeth more resistant to acid attacks from bacteria and sugars.
• Community water fluoridation began in 1945 in the United States as a public health measure.

Last verified on 15-03-2026

Explanation

• Mitochondria are cell organelles responsible for producing energy in the form of ATP (Adenosine Triphosphate) through cellular respiration. 
• They are called the “Powerhouse of the cell” because they provide the energy required for all cellular activities.
• Mitochondria have their own DNA and ribosomes, allowing them to replicate independently.

Last verified on 14-03-2026