Question

Write a note on resistance and ohm's law?

Answer 1

Hint: The collection of physical phenomena connected with the presence and motion of matter with an electric charge is known as electricity. Electricity and magnetism are both components of the electromagnetic phenomena, as defined by Maxwell's equations. Lightning, static electricity, electric heating, electric discharges, and many more common phenomena are all connected to electricity.

Complete step-by-step solution:
Resistance
The electrical resistance of an object is a measure of its resistance to the flow of electric current in electronics and electromagnetism. Electrical resistance and mechanical friction have some conceptual similarities. The ohm is the SI unit for electrical resistance. An object's resistance is mostly determined by the material it is constructed of. Electrical insulators, such as rubber, have a very high resistance and low conductivity, whereas electrical conductors, such as metals, have a very low resistance and great conductivity. Resistivity or conductivity are used to measure this connection. The ratio of voltage V across an item to current I flowing through it is known as its resistance R.
\[R = \dfrac{V}{I}\]
Ohm's Law
According to Ohm's law, the current flowing through a conductor between two locations is proportional to the voltage across the conductor. When the proportionality constant, resistance, is included, the typical mathematical equation that represents this connection emerges.
\[R = \dfrac{V}{I}\]
 where I denote the current through the conductor in amperes, V denotes the voltage measured across the conductor in volts, and R is the conductor's resistance in ohms. Ohm's law indicates that the R in this relationship remains constant regardless of the current.

Note: For most materials, Ohm's law is an empirical law, a generalisation of numerous experiments that have demonstrated that current is roughly proportional to electric field. It is not usually followed and is less basic than Maxwell's equations. Under a high enough electric field, any material will break down, and some materials of importance in electrical engineering are "non-ohmic" under weak fields. On a wide range of length scales, Ohm's law has been observed. It was assumed in the early twentieth century that Ohm's law would fail at the atomic level, but tests have shown that this is not the case.