Multiple choice

The friction in fluid is called _____.

  1. density

  2. surface tension

  3. viscosity

  4. none of the above

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Viscosity is the internal friction in fluids that resists flow. It arises due to intermolecular forces between layers of fluid moving at different velocities. Just as solid friction opposes relative motion between surfaces, viscosity opposes relative motion between fluid layers.