SSC JE Mechanical Engineering 2018 Set 1 Paper

$\left[{\mathit{P}}_{\mathit{C}}=\frac{{\mathit{P}}_{\mathit{N}}}{\cos \mathit{\alpha }}\right]$
Axial Pitch (P${}_{\mathit{C}}$) : It is the distance measured parallel to the axis between similar faces of adjacent teeth, it is the same as circular pitch and is therefore denoted by ${\mathit{P}}_{\mathit{C}}$ where $\mathit{\alpha }$is helix angle.