Self-locking takes place when
a) Coefficient of friction is equal to or greater than the tangent of the helix angle
b) Coefficient of friction is lesser than or equal to the tangent of the helix angle
c) Coefficient of friction is equal to or greater than the tangent of the helix angle
d) None of the mentioned
a) Coefficient of friction is equal to or greater than the tangent of the helix angle
b) Coefficient of friction is lesser than or equal to the tangent of the helix angle
c) Coefficient of friction is equal to or greater than the tangent of the helix angle
d) None of the mentioned