Questions normally not answered by Students in Viva

Here are some questions which are not properly answered by students during Viva.

  1. Name the Physical quantities to be kept constant for Ohm’s law to be true.
  2. State the Principle of a potentiometer. (The students say that potential drop is proportional to length but the constant quantities are not mentioned)
  3. How can we increase the sensitivity of a potentiometer?
  4. Define figure of merit of a galvanometer.
  5. Which has more resistance – a galvanometer or a milliammeter?
  6. How does an LED emit light?
  7. What is the difference between an ordinary diode and an LED?
  8. Define principal axis of a convex lens?
  9. What happens to the focal length of a concave mirror if it is immersed in water?
  10. What are the factors affecting the intrernal resistance of a cell?
  11. What are the difference between primary and secondary cell?
  12. Why can’t we use a dry cell for starting a car?