Practice Test: Question Set - 01
1. A screw is said to be self-locking if its efficiency is
- (A) Equal
to 50%
- (B) More
than 50%
- (C) Less
than 50%
- (D) None
of the above
2. The maximum efficiency of square threaded power is
- (A) 1 -
sin α/1 + sin α
- (B) 1 +
sin α/1 - sin α
- (C) 1 - tan α/1 + tan α
- (D) 1 + tan α/1 - tan α
Where, φ = friction angle
3. A power screw is specified by
- (A) Major
diameter × pitch
- (B) Major
diameter × length
- (C) Mean
diameter × pitch
- (D) Nominal
major diameter
4. Which of the following screw thread is used for lead screw of lathe?
- (A) Square
threads
- (B) Trapezoidal
threads
- (C) Buttress
threads
- (D) V-threads
5. Which of the following screw thread is used for jacks, vices and clamps?
- (A) Square
threads
- (B) Trapezoidal
threads
- (C) Buttress
threads
- (D) Acme
threads
6. The efficiency of square threaded power is maximum when
- (A) α = 60° - φ
- (B) α = 45° - φ
- (C) α = 45° + φ/2
- (D) α = 45° - φ/2
Where, α = helix angle, φ = friction angle
7. The maximum efficiency of square threaded power with friction angle of 30° is
- (A) 25 %
- (B) 33 %
- (C) 47 %
- (D) 41 %
8. Which of the following screw thread is used for transmitting force in one direction?
- (A) Square
threads
- (B) Trapezoidal
threads
- (C) Buttress
threads
- (D) V-threads
9. A screw is said to be over hauling if its efficiency is
- (A) Equal
to 50%
- (B) More than
50%
- (C) Less
than 50%
- (D) None
of the above
10. The efficiency of square threaded power depends upon
- (A) Mean
diameter of screw
- (B) Coefficient
of friction
- (C) Pitch
of screw
- (D) All
the above
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