Question

Define resistance of a material .write si unit of resistance nd define it .

Answer 1

resistance is an opposition to the motion of electrons .This arises as a result of collision of moving electrons with the neighboring atoms.
S.I. unit:
ohm

Answer 2

Question:-

Define resistance of a material .write si unit of resistance nd define it .

Answer :-

✮ What is Resistance ?

Resistance refer to the property of materials that allow the flow of electric current. Resistance certainly opposes the flow of current.

✮ What is the S.I unit of Resistance ?

The unit of resistance is ohms which is represented by the Greek uppercase letter omega Ω.

✮ Formula for Resistance ?

Resistance = voltage drop across a resistor/ current flowing through a resistor

R = { V/I }

R = resistance (Ohms, Ω)

V = voltage difference which is between the two ends of a resistor (Volts, V)

I = the current which flows through a resistor (Amperes, A)

✮ Formula to find resistance in a series circuit ?

Series circuits

The total resistance of the circuit is found by simply adding up the resistance values of the individual resistors: equivalent resistance of resistors in series :

{ R = R1 + R2 + R3 + ...}

A series circuit is shown in the diagram above. The current flows through each resistor in turn.

✮ Formula to find resistance in a parallel circuit ?

You can find total resistance in a Parallel circuit with the following formula:

{ 1/Rt = 1/R1 + 1/R2 + 1/R3 +..}

Note :-

• If one of the parallel paths is broken, current will continue to flow in all the other paths.

• The total resistance of a parallel circuit is NOT equal to the sum of the resistors (like in a series circuit).