Consider the following statements regarding gears :
1. The ratio of number of teeth on the gear to that on the pinion is known as gear ratio.
2. The circle passing through the tips of teeth is called dedendum circle.
3. The circle passing through the roots of teeth is called addendum circle.
4. Backlash is the difference between the space width and the tooth thickness along the pitch circle.
Which of the above statements are correct ?
1
1, 2 and 3 only
2
1 and 4 only
3
2 and 3 only
4
1, 2, 3 and 4