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# Test: Efficiency Of Screws

## 10 Questions MCQ Test Design of Machine Elements | Test: Efficiency Of Screws

Description
This mock test of Test: Efficiency Of Screws for Mechanical Engineering helps you for every Mechanical Engineering entrance exam. This contains 10 Multiple Choice Questions for Mechanical Engineering Test: Efficiency Of Screws (mcq) to study with solutions a complete question bank. The solved questions answers in this Test: Efficiency Of Screws quiz give you a good mix of easy questions and tough questions. Mechanical Engineering students definitely take this Test: Efficiency Of Screws exercise for a better result in the exam. You can find other Test: Efficiency Of Screws extra questions, long questions & short questions for Mechanical Engineering on EduRev as well by searching above.
QUESTION: 1

### Efficiency of screw depends upon lead of the screw.

Solution:

Explanation: Efficiency= WL/[Pπd].

QUESTION: 2

### Efficiency of the screw depends upon helix angle but does not depend on friction angle.

Solution:

Explanation: Efficiency=tan(ἀ)/tan(Ǿ+ἀ) where ἀ=Helix angle and Ǿ=Friction angle.

QUESTION: 3

### Efficiency of the screw _______ with increase of coefficient of friction.

Solution:

Explanation: Efficiency is inversely proportional to tan of the sum of helix and efficiency angle.

QUESTION: 4

Maximum efficiency of a square threaded is given by

Solution:

Explanation: Efficiency=Sin(2ἀ+Ǿ)-Sin Ǿ /Sin(2 ἀ+Ǿ+Sin Ǿ),For max efficiency, sin(2ἀ+ Ǿ)=1.

QUESTION: 5

If friction angle is 30’ then the maximum efficiency of the screw is

Solution:

Explanation: Maximum efficiency=1-sinǾ/1+sinǾ.

QUESTION: 6

Maximum possible efficiency of a self-locking screw is

Solution:

Explanation: For self locking screw Ǿ(friction angle)>ἀ (helix angle), hence efficiency < tanǾ/tan(Ǿ+ἀ) or efficiency < tanǾ(1-tan²Ǿ)/2tanǾ.

QUESTION: 7

In trapezoidal threads, f (coefficient of friction) can be taken as

Solution:

Explanation: The normal force acting on the thread is W sec θ therefore the effect of the thread angle is to increase the frictional force by a term sec θ.

QUESTION: 8

Clutch and coupling can be considered to be same.

Solution:

Explanation: Clutch is a temporary join while coupling is a permanent joint.

QUESTION: 9

Cold rolled components have higher strengths and hardness than hot rolled components.

Solution:

Explanation: During grain re-structuring, original strength of material is lost.

QUESTION: 10

Which of the following are true?

Solution:

Explanation: Properties of cold working.