Worm Gears MCQs : This section focuses on the "Worm Gears". These Multiple Choice Questions (MCQs) should be practiced to improve the Worm Gears skills required for various interviews (campus interview, walk-in interview, company interview), placement, entrance exam and other competitive examinations.
Question 1
A pair of worm gear is written as 2/40/12/6. Calculate the centre distance.
A. 40mm
B. 156mm
C. 200mm
D. 80mm
Question 2
A pair of worm gear is written as 2/40/12/6. Calculate the pitch circle diameter of worm wheel.
A. 72mm
B. 240mm
C. 260mm
D. 320mm
Question 3
A pair of worm gear is written as 2/40/12/6. Calculate the root diameter of the worm wheel.
A. 186.22mm
B. 250.4mm
C. 225.6mm
D. 250.44mm
Question 4
A pair of worm gear is written as 2/40/12/6. Calculate the speed reduction.
A. 2
B. 20
C. 15
D. 6
Question 5
A pair of worm gear is written as 2/40/12/6. Calculate the throat diameter of the worm wheel.
A. 220.5mm
B. 246.4mm
C. 190.44mm
D. 251.7mm
Question 6
Can worm gears be used in steering mechanism?
A. TRUE
B. FALSE
Question 7
If tangential force on worm is 1500N, then axial force on worm wheel will be?
A. 1500N
B. 3000N
C. 1500â2 N
D. 750N
Question 8
If worm helix angle is 30â°, then worm should have at least ___ threads.
A. 5
B. 6
C. 7
D. 8
Question 9
Is it possible to use worm gears in cranes for lifting purpose?
A. TRUE
B. No self-locking and hence not possible
C. Possible up to a threshold load
D. None of the listed
Question 10
The power transmitting capacity of worm gears is high although efficiency is low.
A. TRUE
B. FALSE
Question 11
The worm and worm wheel both are threaded screw.
A. TRUE
B. Worm wheel is a toothed gear
C. Worm is a toothed gear
D. None of the listed
Question 12
The worm helix angle is the _____ of the worm lead angle.
A. Complement
B. Half
C. Double
D. Supplement
Question 13
Which of the following is not true about worm gears?
A. Compact
B. Smooth and silent operation
C. Low speed reduction
D. All the mentioned are true
Question 14
Worm gear drives are used to transmit power between two non-intersecting shafts which are generally at right angles to each other.
A. TRUE
B. FALSE
Question 15
Calculate the lead angle of the worm gear for maximum efficiency if θ = 90° and the coefficient of friction is 0.05.
A. 48.21°
B. 42.23°
C. 43.57°
D. 46.43°
Question 16
Calculate the maximum efficiency of the worm gears which have a friction angle of 0.06.
A. 88.71%
B. 83.23%
C. 89.91%
D. 86.49%
Question 17
Find the helix angle of the worm if the pitch of the worm gear is 12 mm and the pitch diameter is 50 mm.
A. 8.687°
B. 11.231°
C. 9.212°
D. 10.319°
Question 18
Find the maximum efficiency if the lead angle is given to be 10° and the coefficient of friction is 0.07.
A. 79.82%
B. 72.23%
C. 76.29%
D. 70.72%
Question 19
Find the speed of the gear if the worm is a three start worm rotating at 500 rpm. The gear has 20 teeth.
A. 125 rpm
B. 100 rpm
C. 75 rpm
D. 50 rpm
Question 20
For a two start worm gear having a pitch of 20 mm and a lead angle 12°, find the centre distance if the larger gear has 25 teeth.
A. 148.22 mm
B. 124.93 mm
C. 121.19 mm
D. 109.53 mm
Question 21
The angle at which the teeth are inclined to the normal of the axis of rotation is called _______________
A. pitch angle
B. lead angle
C. normal angle
D. joint angle
Question 22
The distance between corresponding points on adjacent teeth measured along the direction of the axis is called ____________
A. joint line
B. normal link
C. axial pitch
D. lead
Question 23
The distance by which a helix advances along the axis of the gear for one turn around is called _____________
A. joint line
B. normal link
C. axial pitch
D. lead
Question 24
The driven gear in the worm gear is a helical gear. True or false?
A. TRUE
B. FALSE
Question 25
What is the centre distance for the worm gear?
A. (mn/2)(T1 cotλ1 – T2)
B. (mn/2)(T2 cotλ1 + T1)
C. (mn/2)(T2 cotλ1 – T1)
D. (mn/2)(T1 cotλ1 + T2)
Question 26
What is the formula to calculate maximum efficiency of a worm gear?
A. (1+sinø)/(1-sinø)
B. (1-sinø)/(1+sinø)
C. (tan(λ1-ø))/tan λ1
D. (tan(λ1+ø))/tan λ1
Question 27
What is the velocity ratio of worm gears?
A. (lπ)/d2
B. (πd2)/l
C. l/(πd2)
D. d2/(lπ)
Question 28
When large gear reductions are needed _________ gears are used.
A. helical
B. spur
C. worm
D. bevel
Question 29
Which is of these is an advantage of worm gear?
A. It is expensive
B. Has high power losses and low transmission efficiency
C. Produce a lot of heat
D. Used for reducing speed and increasing torque
Question 30
For a bevel gear having the pitch angle θ, the ratio of formative number of teeth (TE) to actual number of teeth (T) is
A. 1/sin θ
B. 1/cos θ
C. 1/tan θ
D. sin θ cos θ
Question 31
In worm gears, the angle between the tangent to the thread helix on the pitch cylinder and the plane normal to the axis of worm is called
A. pressure angle
B. lead angle
C. helix angle
D. friction angle
Question 32
The axial thrust on the worm (WA) is given by
A. WA = WT . tan φ
B. WA = WT / tan φ
C. WA = WT . tan λ
D. WA = WT / tan λ
Question 33
The face angle of a bevel gear is equal to
A. pitch angle – addendum angle
B. pitch angle + addendum angle
C. pitch angle – dedendum angle
D. pitch angle + dedendum angle
Question 34
The normal lead, in a worm having multiple start threads, is given by
A. lN = l / cos λ
B. lN = l . cos λ
C. lN = l
D. lN = l tan
Question 35
The number of starts on the worm for a velocity ratio of 40 should be
A. single
B. double
C. triple
D. quadruple
Question 36
The root angle of a bevel gear is equal to
A. pitch angle – addendum angle
B. pitch angle + addendum angle
C. pitch angle – dedendum angle
D. pitch angle + dedendum angle
Question 37
The worm gears are widely used for transmitting power at ______________ velocity ratios between non-intersecting shafts.
A. high
B. low
C. medium
D. none of the mentioned
Question 38
When bevel gears having equal teeth and equal pitch angles connect two shafts whose axes intersect at right angle, then they are known as
A. angular bevel gears
B. crown bevel gears
C. internal bevel gears
D. mitre gears