# MCQs on Mechanical Actuating Systems – Gear and Gear Trains – 1

1 - Question

What is the module of a gear if its pitch diameter is 10mm and it contains 5 teeth?
a) 2
b) 3
c) 4
d) 5
Explanation: Given: Pitch diameter = 10mm No. Of teeth=5 teeth Module=Pitch diameter/No. Of teeth Module=>10/5 =2.

2 - Question

What is the pitch of a gear if the gear contains 30 teeth and diameter of the gear is 6 inches?
a) 2
b) 3
c) 4
d) 5
Explanation: Given: No. Of teeth=30 teeth Diameter=6 inches Pitch=Number of teeth/Diameter Pitch=30/6=5.

3 - Question

What is the torque offered by a gear, if the tangential force is 20 N and radius of the gear is 1m?
a) 5Nm
b) 15Nm
c) 20Nm
d) 2.55Nm

4 - Question

What is the radius of a gear, if torque generated by the gear is 20Nm and the tangential force is 5N?
a) 5m
b) 15m
c) 10m
d) 4m
Explanation: Given: No. Of teeth=30 teeth Diameter=6 inches Pitch=Number of teeth/Diameter Pitch=30/6 = 5.

5 - Question

The pitch of a gear is defined as the number of teeth per unit pitch circle radius.
a) True
b) False
Explanation: The pitch of a gear is not the number of teeth per unit pitch circle radius. It is defined as the number of teeth per unit pitch circle diameter. The diameter is taken in inches.

6 - Question

The radial distance between root circle and pitch circle is called addendum.
a) True
b) False
Explanation: The radial distance between root circle and pitch circle is not called addendum. The radial distance between root circle and pitch circle is called dedendum. Radial distance between addendum circle and pitch circle is called addendum.

7 - Question

What is the velocity ratio of two gears if the driver gear has 15 teeth and driven gear has 5 teeth?
a) 2:1
b) 3:1
c) 4:3
d) 5:1
Explanation: Given: No. Of teeth of driver gear=15 No. Of teeth of driven gear=5 Velocity ratio=No. of teeth of driver gear/No. of teeth of driven gear Velocity ratio => 15/5=3:1.

8 - Question

What is the torque offered by a gear, if the tangential force is 10N and radius of the gear is 0.5m?
a) 5Nm
b) 15Nm
c) 10Nm
d) 2.55Nm
Explanation: Given: Tangential force=10N Radius of the gear=0.5m Torque=tangential force (F)*Radius(R) Torque=10*0.5 => 5Nm.

9 - Question

What is the radius of a gear, if torque generated by the gear is 20Nm and the tangential force is 5N?
a) 5m
b) 4m
c) 10m
d) 2m
Explanation: 4m is the radius of a gear, if torque generated by the gear is 20Nm and the tangential force is 5N. Since the formula for torque(T) is tangential force (F)*Radius(R), so radius=Torque(T)/Tangential force(F) which gives radius = 20Nm/5m => 4m.

10 - Question

What is the module of a gear if its pitch diameter is 15mm and it contains 3 teeth?
a) 2
b) 3
c) 4
d) 5
Explanation: Given: Pitch diameter = 15mm No. Of teeth=3 teeth Module=Pitch diameter/No. Of teeth Module=>15/3=5.

11 - Question

What is the velocity ratio of two gears if the driver gear has 20 teeth and driven gear has 10 teeth?
a) 2:1
b) 3:2
c) 4:3
d) 5:1
View Answer Answer: a Explanation: Given: No. Of teeth of driver gear=20 No. Of teeth of driven gear=10 Velocity ratio=No. of teeth of driver gear/No. of teeth of driven gear Velocity ratio => 20/10=2:1.

12 - Question

What is the speed ratio of two gears if the speed of the driver gear has 20 km/hr and driven gear has 10km/hr?
a) 2:1
b) 3:2
c) 4:3
d) 5:1
View Answer Answer: a Explanation: Given: Speed of the driver gear=20km/hr Speed of the driven gear = 10km/hr Speed ratio=speed of the driver gear/speed of the driven gear Speed ratio=>20/10=2:1.

13 - Question

What is the speed ratio of two gears if the speed of the driver gear has 25 km/hr and driven gear has 10km/hr?
a) 2:1
b) 3:2
c) 4:3
d) 5:2
Explanation: Given: Speed of the driver gear=25km/hr Speed of the driven gear = 10km/hr Speed ratio=speed of the driver gear/speed of the driven gear Speed ratio=>25/10=5:2.

14 - Question

What is the train value of a gear train if the velocity ratio is 2:5?
a) 2:1
b) 3:2
c) 4:3
d) 5:2
Explanation: Given: velocity ratio=2:5 Train value=1/(velocity ratio) Train value=1/(2:5)=5:2.

15 - Question

What is the train value of a gear train if the velocity ratio is 2:1?
a) 2:1
b) 1:2
c) 4:3
d) 5:2