The opposition to the flow of electron is called resistance.
Resistance is the property of a material due to which it opposes the flow of electric current. "R" represents it. It, s unit is called ohm. Ohm is represented by omega (Ω)
Mille Ω = 10-3 Ω
Micro Ω = 10-6 Ω
Nino Ω = 10-9 Ω
Pico Ω = 10-12 Ω
133 Ω = 1 kilo Ω
106 Ω = 1 mega Ω
When one volt is given to a circuit due to which one-ampere current flows then the curcuit resistance will be 1Ω.
The resistance will be one ohm when ampere current flows in a circuit in one second and one-joule energy produce.
Conductance is the propertey of material due to which it allows the flow of electric current. "G" represects it. It unit is called Simon.