Machine Design
The dedendum circle diameter is equal to (where φ = Pressure angle)

Pitch circle diameter × cosφ
Clearance circle diameter × cosφ
Addendum circle diameter × cosφ
Pitch circle diameter × sinφ

ANSWER DOWNLOAD EXAMIANS APP

Machine Design
The cracks in helical springs used in railway carriages usually start on the inner side of the coil because of the fact that

It has a lower curvature than the outer side
It is more stretched than the outer side during the manufacturing process
It is subjected to a higher stress than the outer side
It is subjected to a higher cyclic loading than the outer side

ANSWER DOWNLOAD EXAMIANS APP