UPRVUNL’21 ME : Daily Practices Quiz: 06.08.2021

Quiz: Mechanical Engineering
Exam: UPRVUNL
Topic: Miscellaneous

Each question carries 1 mark
Negative marking: 1/4 mark
Time: 8 Minutes

Q1. Young’s modulus is defined as the ratio of

(a) Volumetric stress and volumetric strain

(b) Lateral stress and lateral strain

(c) Longitudinal stress and longitudinal strain

(d) Longitudinal strain and lateral strain

Q2. Rivets undergo single shear in

(a) Lap joint and single-cover butt joint

(b) single-cover butt joint and double-cover butt joint

(c) Lap joint and double-cover butt joint

(d) Lap joint only

Q3. Strain energy theory was postulated by __________.

(a) St. Venant

(b) Haigh

(c) Rankine

(d) Tresca

Q4. Perpetual motion machine of second kind violates the

(a) First law of thermodynamics

(b) Kelvin-Planck statement

(c) Clausius statement

(d) Third law of thermodynamics

Q5. For high speed engines, the cam follower should move with-

(a) uniform velocity

(b) Cycloidal motion

(c) Simple harmonic motion

(d) Uniform acceleration and retardation.

Q6. Thermal diffusivity of a substance is

(a) Inversely proportional to thermal conductivity

(b) Directly proportional to thermal conductivity

(c) Directly proportional to the square of thermal conductivity

(d) Inversely proportional to the square of thermal conductivity

Solutions

S1. Ans (c)

Sol. Young’s modulus is defined as the ratio of longitudinal stress and longitudinal strain.

i.e. E=σ/∈

S2. Ans.(a)

Sol.

Lap joint: Rivets undergo single shear

Single cover butt joint: Rivets undergo single shear.

Double cover butt joint: Rivets undergo double shear.

S3. Ans.(b)          

Sol. Strain energy theory is also known as Haigh’s theory because it is postulated by Haigh.

S4. Ans (b)

Sol. Perpetual motion machine of the second kind is a machine which produces work while exchanging heat from a single heat source. Which violates Kelvin-Planck statement of Second law of thermodynamics.

Q5. Ans. (b)

Sol. for high speed engines, the cam followe should moves with cycloidal motion as there are no abrupt changes in the velocity and the acceleration at any stage of the motion. Thus, it is most ideal cam profile for high speed follower motion.

S6. Ans. (b)

Sol. Thermal diffusivity- Thermal diffusivity is the thermal conductivity divided by density and specific heat capacity at constant pressure. It measures the rate of heat transfer of heat of a material from the hot end to the cold end. It has the SI derived unit of m²/s.

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