Question

8. Define the units for the following

a) Resistance b) resistivity c) current d) voltage e) potential difference​

Answer 1

Answer:

a) Resistance is a measure of the opposition to current flow in an electrical circuit. Resistance is measured in ohms, symbolized by the Greek letter omega (Ω). Ohms are named after Georg Simon Ohm (1784-1854), a German physicist who studied the relationship between voltage, current and resistance.

b) Electrical resistivity and its inverse, electrical conductivity, is a fundamental property of a material that quantifies how strongly it resists or conducts electric current. A low resistivity indicates a material that readily allows electric current. Resistivity is commonly represented by the Greek letter ρ.

c) electric current is the rate of flow of electric charge past a point or region. An electric current is said to exist when there is a net flow of electric charge through a region. Electric charge is carried by charged particles, so an electric current is a flow of charged particles

d) Voltage, electric potential difference, electric pressure or electric tension is the difference in electric potential between two points. The difference in electric potential between two points in a static electric field is defined as the work needed per unit of charge to move a test charge between the two points.

e) Voltage, electric potential difference, electric pressure or electric tension is the difference in electric potential between two points. The difference in electric potential between two points in a static electric field is defined as the work needed per unit of charge to move a test charge between the two points.

Answer 2

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☛Resistance:- Resistance is the physical property of a substance in which it opposes the the flow of current i.e, electrons

• SI unit of resistance is ohms.

• Resistance is directly proportional to the length and temperature while it is inversely proportional to the cross section area of the material.

☛Resistivity:-Resistivity is the physical property of a particular substance which is having particular dimensions.

• SI unit of resistivity is ohm metre.

• Resistivity is only proportional to the nature and temperature of the particular materials.

☛Electric Current :- It is the potential difference between the ends of the wire which makes the electric charges or current to flow in the wire.

• In other words electric current is a flow of electric charges (electrons) in a conductor such as a metal wire.

• SI unit of electric current is ampere.

☛ Voltage :-voltage is defined as the energy per unit charge.

• SI unit of voltage is volts.

• Voltage is measured by using voltmeter.

☛ Potential difference:- The difference in electric potential between two points is known as potential difference.

Potential difference $\bf\:=\dfrac{work\:done}{Quality\:of\:charge\:moved}$

• SI unit of potential difference is volt.