"A crack will extend only when the total potential energy of the system of applied forces and material decreases or remain constant with an increase in crack length" - Who has given this concept?

A. rock strength B. RQD C. ground water condition D. layers thickness

A. 5 - 10 KN B. 15 - 20 KN C. 50 - 60 KN D. 120 - 130 KN

A. point load test B. servocontrolled test C. displacement test D. post peak test

A. 1.25 B. 1.50 C. 2.25 D. 1.00