Q13: Pakistan Affairs MCQ 2009

**The most suitable thermometer for measuring the boiling point of water is:**A) Mercury thermometerB) Alcohol thermometerC) Bimetallic thermometerD) None of these Show Answer Correct Answer: A – Mercury thermometer

**Optical fibre operates on the principle of:**A) Tyndall effectB) Photoelectric effectC) Laser technologyD) Total internal reflection Show Answer Correct Answer: D – Total internal reflection

**During combustion of petrol in a car engine, energy is converted into:**A) ChemicalB) MechanicalC) ElectricalD) None of these Show Answer Correct Answer: B – Mechanical

**The speed of sound in dry air at 20°C is about:**A) 130 meters per secondB) 230 meters per secondC) 330 meters per secondD) 550 meters per second Show Answer Correct Answer: C – 330 meters per second

**How long does our Earth take to turn about its axis?**A) One hourB) 23 hoursC) 24 hoursD) None of these Show Answer Correct Answer: C – 24 hours