Q1: Size reduction mechanism used in Jaw crushers is

ANS:B - compression

The size reduction mechanism predominantly used in Jaw crushers is compression. Here's why:

1. Compression:
   • Jaw crushers operate by compressing rock between two surfaces, one of which opens and closes like a jaw (referred to as a swing jaw).
   • The material is crushed by the compression forces generated by the movable jaw against the fixed jaw.
2. Other Mechanisms:
   • Impact: While there may be some impact involved when the material is initially fed into the crushing chamber, the primary mechanism once crushing begins is compression.
   • Cutting: Cutting action is not typically a significant mechanism in jaw crushers.
   • Attrition: Attrition involves rubbing and friction between particles, which is not the primary mode of size reduction in jaw crushers.