Question

The SI unit of resistance is

• A. coulomb
• B. joule
• C. ampere
• D. ohm

Hint:

One ohm is the resistance when a potential difference of 1 volt produces a current of 1 ampere.

Answer 1

The Correct Option is D

Step 1: Definition of Resistance:
Resistance is the property of a conductor that opposes the flow of electric current. It is denoted by $R$. Step 2: SI Unit:
According to Ohm’s law: \[ R = \frac{V}{I} \] where,
$V =$ Potential difference (in volts, V)
$I =$ Current (in amperes, A)
Thus, \[ \text{Unit of } R = \frac{\text{volt}}{\text{ampere}} = \Omega \, (\text{ohm}) \] Step 3: Analysis of Other Options:
Coulomb → unit of charge.
Joule → unit of energy.
Ampere → unit of electric current.
Ohm → correct SI unit of resistance.
Step 4: Final Answer:
The SI unit of resistance is ohm ($\Omega$).