# MCQs on System of Gear Tooth

1 - Question

There are ____ standard systems for the shape of gear teeth.

a) 1
b) 2
c) 3
d) 4

Explanation: 14.5⁰ full depth involute system, 20⁰ full depth involute system and 20⁰ stub involute system.

2 - Question

When the number of teeth reaches infinity, circle radius approaches infinity the gear becomes an infinite loop.

a) True
b) False

Explanation: It becomes a rack with straight sided teeth.

3 - Question

Which of the following statements are not true?

a) Increasing pressure angle improves the tooth strength
b) Contact duration is decreased with increase in pressure angle
c) 20⁰ pressure angle has quieter operation then 14.5⁰
d) All of the statements are true

Explanation: Lower the pressure angle, quieter is the operation. Lower the pressure angle, lower is the breadth of the tooth at root.

4 - Question

20⁰ stub involute system have comparatively smaller interference.

a) True
b) False

Explanation: They have shorter addendum and shorter dedendum.

5 - Question

Which of the following have stronger teeth?

a) Stub teeth
b) Full depth teeth
c) Both have equal strength
d) Can’t be determined

Explanation: Smaller moment arm of bending force leads to stronger stub teeth.

6 - Question

As the module increases, index of size of gear decreases.

a) True
b) False

Explanation: Module is the measure of size of index of the gear tooth.

7 - Question

Crowning is an abrasive process that debars the gear strength.

a) True
b) False

Explanation: Crowningis used to strengthen the tooth.

8 - Question

Inaccuracies in tooth profile lead to concentration of pressure on the middle of tooth. crowning.

a) True
b) False

Explanation: Inaccuracies lead to shift of pressure at the end of tooth which can be improved by

9 - Question

A pair of spur gears consist of 25 teeth pinion meshing with a 115 teeth gear. The module is 5mm. Calculate the centre distance.

a) 280mm
b) 269mm
c) 350mm
d) 305mm

Explanation: C=m(z(p)+z(g))/2.

10 - Question

A pair of spur gears consist of 25 teeth pinion meshing with a 115 teeth gear. The module is 5mm. Calculate pitch circle diameter of the pinion.

a) 95mm
b) 105mm
c) 115mm
d) 125mm

Explanation: D=5×25.

11 - Question

A pair of spur gears consist of 25 teeth pinion meshing with a 115 teeth gear. The module is 5mm. Calculate the pitch circle diameter of the gear.

a) Cannot be determined
b) 31mm
c) 475mm
d) 575mm

Explanation: D=5×115.

12 - Question

A pair of spur gears consist of 25 teeth pinion meshing with a 115 teeth gear. The module is 5mm. Calculate the addendum.

a) None of the listed
b) 4.75mm
c) 5.25mm
d) 5mm

Explanation: H=m=5mm.

13 - Question

A pair of spur gears consist of 25 teeth pinion meshing with a 115 teeth gear. The module is 5mm. Calculate the dedendum.

a) 4.75mm
b) 5mm
c) 6.25mm
d) 6.68mm

Explanation: H=1.25xm=1.25x5mm.

14 - Question

A pair of spur gears consist of 25 teeth pinion meshing with a 115 teeth gear. The module is 5mm. Calculate the tooth thickness.

a) 6.23mm
b) 5.44mm
c) 7.854mm
d) 8.16mm

Explanation: T=1.5708xm=1.5708x5mm.

15 - Question

A pair of spur gears consist of 25 teeth pinion meshing with a 115 teeth gear. The module is 5mm. Calculate the bottom clearance.

a) None of the listed
b) 1.75mm
c) 2.5mm
d) 1.25mm