Question

• With respect to Ohm's Law, explain in your own words what is meant when it is said that there is "a linear response between voltage and current."
• Name a specific device in which Ohm's Law is a good description of the relationship between current and voltage, and one for which it is not. Do your best to explain this failure in terms of the basic properties of electrons flowing through a conducting material.
• Describe the temperature response of resistors in a circuit. Are there any devices which take advantage of this property? If so, explain how they work in terms of the properties of electrons.

Answer 1

linear response meaning:-

with the increase of one quantity the other parameter related with linear response with the previous one increases linearly. If voltage increases in a passive electric circuit ( passive means the circuit does not consist of any active electric elements ) the current also increases in a linear way. The slope of these two quantities is straight line.

Examples:-

Potentiometer obeys ohm's law in a good way.

Diode does not obey ohm's law, it is termed as non ohmic conductor or active elements.

Failure of ohm's law in diode reason:-

the electron which is the main carrier in the conducting medium of diode increases in avalanche way after some time and no. of free electron increases rapidly. So no linear relationship holds.

Temperature response of resistors in a circuit:-

As explained earlier, electrons mainly take part in conduction, Resistance is the obstacle faced by these freely moving electrons for any type of conductor. With the increase of temperature the vibration of the materials in any medium increases as well as the obstacles, so resistance increases with the increase of temperature.

Device takes advantage of this property:-

Electric Heater, As explained the reason why resistance increases in a resistor with temperature, The resistance is made as greater as possible in Heater.

Do comment for any further doubts, if any point is missing.