The fracture stress according to Orowan’s theory of brittle fracture is __________ (where E is Yong’s modulus, ϒp is the plastic work required to extend the crack wall of the length 2a).

The fracture stress according to Orowan’s theory of brittle fracture

1.	The fracture stress according to Orowan’s theory of brittle fracture is __________ (where E is Yong’s modulus, ϒp is the plastic work required to extend the crack wall of the length 2a).
A.	(Eϒp/a)1/2
B.	(Eϒp/a)
C.	(Eϒp/2a)1/2
D.	(Eϒp/2a)
Answer» B.