Resistance per unit length of a given wire viva questions with answers

 VIVA QUESTIONS WITH ANSWERS

Experiment No - 01: To determine the resistance per unit length of a given wire by plotting a graph for Current (I) versus Potential difference (V)

01. State Ohm's law?

Answer: Ohm's law states that the electric current flowing through a conductor is directly proportional to the potential difference across its ends provided that physical conditions like temperature and pressure remain the same.

02. Why a large amount of current is not preferred in the experiment?

Answer: When a large current passes, the conductor gets heated more, and hence its resistance changes.

03. What is the reciprocal of resistance? With what unit has it been measured?

Answer: Reciprocal resistance is conductance. It's measured in terms of mho or siemens.

04. What is the resistance of a conductor?

Answer: It is the opposition offered by the conductor for the flow of current through the conductor.

05. How the resistance of the conductor varies with the length of the conductor?

Answer: The resistance of the conductor is directly proportional to its length.

06. What is an Ohmic conductor? Give an example of it.

Answer: The conductor wishes always ohm's law is called an ohmic conductor. Example: silver, copper, aluminum, etc 

07. What is the S I unit of Resistance?

Answer: ohm 

08. In the above experiments two seats of readings were taken. The conductor is heated and two more voltage and current readings were taken. Will the four points form a straight line in the graph? why?

Answer: No. Because the resistance change with the temperature. Hence 2 points corresponding to the readings taken after heating the conductor from a different straight line.

09. What is the resistance of an open key?

Answer: Infinite.

10. Which physical quantity does the slope of the I - V graph gives?

Answer: Conductance.

11. Which physical quantity does the slope of the I - V graph gives?

Answer: Resistance.

12. How do you conclude that the conductor used in the above experiment has obeyed ohm's law?

Answer: I - V graph obtained is a straight line. Hence ohm's law is obeyed.

13. On what factors does the resistance of a conductor depend?

Answer: Length of the conductor, area of a cross-section, type of conductor, and temperature.

14. Length of the material is halved. What happens to its resistance?

Answer: Resistance will be halved.