SSC Selection Post 2020 PYQ — Question 48

The correct answer is option 1 i.e. Specific resistance.

 

Specific resistance, also known as resistivity, is not dimensionless. It has the unit ohm-meter and dimensions of ML³T⁻³A⁻². It measures how strongly a material opposes the flow of electric current. In contrast, refractive index, angle of friction, and specific gravity are all dimensionless quantities as they are expressed as ratios without physical units. These dimensionless values are useful for comparing properties without depending on specific measurement units, unlike specific resistance, which depends on physical dimensions and units.