Explanation

• The Crude Birth Rate (CBR) is the number of live births per 1,000 people in a population in one year.
• It is calculated by dividing the total live births during a year by the mid-year population and multiplying by 1,000.
• It is commonly used to measure population growth and compare birth levels between countries.

Last verified on 12-11-2026

Explanation

Explanation

• The SI unit of force is the newton (N).
• 1 N = the force needed to accelerate 1 kg of mass by 1 m/s²
• Derived unit: N = kg·m/s²
• Named after Sir Isaac Newton
• Based on F = ma (Newton's second law)

Additional information:

1. The metre, unit of length — symbol m
2. The kilogram, unit of mass — symbol kg
3. The second, unit of time — symbol s

Last verified on 09-11-2026

Explanation

• White blood cells (leukocytes) are part of the immune system.
• They play a key role in defending the body against infections, diseases, and foreign invaders.
• They help maintain overall health.

Last verified on 09-11-2026

Explanation

• The poles experience six months of the day and six months of the night.
• This is since earth is tilted on its axis.
• Also, due to this, each pole is tilted towards and away from the sun for about six months.
• When the North Pole is tilted towards the sun, it has continuous daylight.

Last updated 08 Nov 2026 by NA

Explanation

• The SI unit of energy is the Joule (J).
• It is the unit of energy, work, and heat.

Additional information:

• 1 Joule (J) = 1 Newton × 1 meter
• Calorie – 1 cal = 4.184 J
• Kilowatt-hour (kWh) – 1 kWh = 3.6 × 10⁶ J
• Electronvolt (eV) – 1 eV ≈ 1.602 × 10⁻¹⁹ J
• Erg (CGS unit) – 1 erg = 10⁻⁷ J

Last verified on 17-01-2026

Explanation

• Alexander Graham Bell is credited as the inventor of the telephone.
• He was awarded the first successful patent for it.
• The telephone was invented in 1876.
• Bell made the first-ever telephone call to his assistant Thomas Watson.

Last updated by NA on 06-11-2026

Explanation

Albert Einstein 

- Profession: Theoretical physicist.

- Century: One of the most influential physicists of the 20th century.

- 1905: Published four landmark scientific papers.

- Nobel Prize: Awarded for his explanation of the photoelectric effect, not the Special Theory of Relativity.

Explanation

• The average distance from the Earth to the Sun is approximately 150 million kilometers.
• It is also called 1 astronomical unit (or AU).

Last updated by NA on 04-11-2026

Explanation

• Iodine deficiency causes goiter, an enlargement of the thyroid gland.
• Iodine is essential for the production of thyroid hormones.
• Severe iodine deficiency during pregnancy or early childhood can impair brain development.

Last verified on 07-09-2026