Science titbits


Compiled by, 
Dr. M Kanagasabapathy

1. Element with 100 protons is Fermium (Fm).

2. First commercial microprocessor, Intel 4004 was released in the year 1971.

3. Ebola virus belongs to Filoviridae family (single-stranded negative-sense RNA viruses).

4. Newtonian fluids have constant viscosity with shear rate directly proportional to shear stress.

5. Magnetic Permeability -  ability of a material to form an internal magnetic field (magnetization) under the applied magnetic field.

6. Wavelength range of infrared (IR) waves is 780 nanometers to 1 millimetre. 

7. Teeth enamel (hardest substance in the body) contains calcium hydroxyapatite, Ca10 (PO4)6 (OH)2.

8. Inductance - tendency of an electrical conductor to oppose a change in the electric current flowing through it. Flow of electric current causes magnetic field around the conductor and it depends on the magnitude of the current.

9. Auxins are an important plant growth hormone and naturally occurring auxin is indole-3 acetic acid.

10. TMT 500 Steel bar - TMT means Thermo Mechanical Treatment and 500 refers to yield strength (maximum limit of elastic behaviour) in mPa of the steel.

11. Yeast, Saccharomyces cerevisiae is used in the manufacture of ethanol.

12. Specific energy (in Wh/kg) of Lithium ferro phosphate battery is 90–160, and for lead-acid battery is 35–40.

13. Tenofovir or entecavir antiviral drug is used to treat Hepatitis B viral infections.

14. Tin (Sn, atomic number 50) has maximum number (10) of stable isotopes.

15. Recycling number (enclosed inside a triangle of three arrows) for low density polyethylene (LDPE) is 4, polyvinyl chloride (PVC) is 3 and for high-density polyethylene (HDPE) is 2.

16. Atmega328 microcontroller used in Arduino board has 28 pins, 20 pins for I/O, 14 digital I/O pins (6 as PWM outputs and 6 as analog I/O). 2 pins are for crystal oscillator (clock pulse), 2 pins (Vcc and GND) to power.

17. Chlorophyll absorbs mainly in blue (400 and 500 nm) and red (650 to 680 nm) region.

18. Bone mineral density (BMD) test can identify osteoporosis and bone density. Commonly used BMD test is called central dual-energy X-ray absorptiometry (central DXA test).

19. Polyurethane foam is produced by the polymeric reaction between diisocyanates with polyols.

20. Sidereal day - Time taken for a planet to complete a spin, for one full rotation. A sidereal day and the rotation speeds of planets are:
Mercury: 58d 16h, 10.83 km/h
Venus: 243d 26m, 6.52 km/h
Earth: 23h 56m, 1574 km/h
Mars: 24h 36m, 866 km/h
Jupiter: 9h 55m, 45583 km/h
Saturn: 10h 33m, 36840 km/h
Uranus: 17h 14m, 14794 km/h
Neptune: 16h, 9719 km/h

21. Class I preservatives are natural and class II preservatives are artificial. Examples for class two preservatives are sorbitol, salts of benzoic acid and nitrites, nitrates of sodium and potassium.

22. Kaprekar's constant (Indian mathematician) is 6174.
Take any four-digit number. Arrange the digits in descending order and ascending order 
(with leading zeros, if necessary) to get two four-digit numbers. Subtract the smaller number from the bigger number. On repeating it will end with 6174, in at most 7 iterations. 
Example with 2011:
2110 - 0112 = 1998
9981 - 1899 = 8082
8820 - 0288 = 8532
8532 - 2358 = 6174

23. Javascript with HTML code for user input.
  <label for="user-input">Enter text:</label>
  <input type="text" id="user-input" name="user-input">
  <button type="submit" onclick="handleSubmit()">Submit</button>
  function handleSubmit() {
    const userInput = document.getElementById("user-input").value;
    alert("The entered content is: " + userInput);

24. Packing factor (fraction of volume occupied by atoms) for crystal structures:
Hexagonal Close Packed (HCP): 0.74
Face Centered Cubic (FCC), (CCP): 0.74
Body Centered Cubic (BCC): 0.68
Simple Cubic: 0.52
Diamond Cubic: 0.34 

25. A normal absolute eosinophil (type of leukocyte or WBC) count ranges from 0 to 500 cells per microliter (<0.5 x 10^9/L) or less than 5% of total white blood cells count. Eosinophilia - more than normal amount of eosinophils. Eosinopenia - less than the normal amount of eosinophils.  

26. Wet-bulb temperature (WBT) is the temperature measured by a thermometer covered by a water-soaked (water at ambient temperature) cloth.
Dry-bulb temperature (DBT) is the ambient temperature measured by a thermometer exposed to the air, but not with water-soaked cloth. At 100% relative humidity, WBT is equal to the air temperature (or DBT) and at lower humidity the WBT is lower than DBT because of cooling by water evaporation.

27.Three omega−3 fatty acids for human physiology are:
α-linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).
ALA can be found in plants, whereas DHA and EPA are found in algae and fish.

28. Structure of the essential amino acid,  Tryptophan is:
IUPAC name: 2-amino-3-(1H-indol-3-yl)propanoic acid

29. Lethal dosage (rat-based, LD50)of sucrose and glucose are 29.7 mg/kg and 25.8 mg/kg respectively. For water, it is 90 mg/kg.

30. Lethal dosage (LD50) of botulinum toxin (neuro toxin from Clostridium botulinum - gram positive, anaerobic bacteria) is very low and is about 1 ng/kg.