Which of the following is correct for a gear? [Where, Pc = Circular pitch, D = Diameter of pitch circles, T = Number of teeth on the gear, Pd = Diametral pitch, m = Module.]
1
\({m}={\frac{T}{D}}\)
2
\(P_{d}={\frac{\pi}{P_{c}}}\)
3
\(P_{c}={\frac{D}{T}}\)
4
\(P_{d}={\frac{\pi D}{T}}\)