Quiz: Mechanical Engineering 15th June

Quiz: Mechanical Engineering
Exam: AE/JE
Topic: Miscellaneous

Each question carries 1 mark
Negative marking: 1/4 mark
Time: 10 Minutes

Q1. When the flow parameters at any given instant remain same at every point, then flow is said to be
(a) quasi static
(b) steady state
(c) laminar
(d) uniform

Q2. The property of a fluid which enables it to resist tensile stress is known as
(a) compressibility
(b) surface tension
(c) cohesion
(d) adhesion

Q3. Which of the following is not an extensive property?
(a) entropy
(b) enthalpy
(c) internal energy
(d) density

Q4. The specific speed of a pump is defined as the speed of a unit of such a size that
(a) it delivers unit discharge at unit head.
(b) it delivers unit discharge at unit power.
(c) it requires unit power per unit head.
(d) it produces unit horse power with unit head.

Q5. Venturimeter is used to measure flow of fluids in pipes when pipe is
(a) horizontal
(b) vertical, flow downwards
(c) vertical, flow upwards
(d) in any position

Q6. Fluidity is greatly influenced by
(a) carbon content of molten metal
(b) melting temperature of molten metal
(c) inoculant addition
(d) pouring temperature of molten metal

Q7. Hardness of steel depends upon amount of _.
(a) Pearlite
(b) Ferrite
(c) Cementite
(d) Martensite

Q8. Concentric helical springs should be
(a) wound in the same direction
(b) wound with opposite hand helices
(c) could be wound in any direction
(d) Direction of winding depends on the load to be carried

Q9. Gear teeth are made harder to avoid
(a) greater compressive stress in bending
(b) tensile strength
(c) abrasion
(d) wear

Q10. The vehicle moving on a level circular path will exert pressure such that _.
(a) the reaction on the outer wheels will be more
(b) the reaction on the inner wheels will be more
(c) the reaction on the inner wheels as well as on the outer wheels will be equal
(d) it depends on the speed

Solutions
S1. Ans(d)
Sol. uniform flow may be defined as the flow in which the velocity at every cross-section area will be same. It can also say that the parameter of flow does not change with respect to space is known as uniform flow.

S2. Ans(c)
Sol. The intermolecular attraction force between same type of molecules is called cohesion.

S3. Ans(d)
Sol. Extensive property depend on the system size or the amount of material in the system. Entropy, Enthalpy, Internal energy increase with increase mass of the system but we cannot say that density will increase with increase with mass and density is intensive property.

S4. Ans(a)
Sol. Specific speed (Ns) of the pump is defined as the speed of any unit of the series of such size that it delivers unit discharge at unit speed. Specific Speed of Pump is a method of characterizing pumping conditions and it may be used to determine the most appropriate pump design for a given application.

S5. Ans(d)
Sol. Venturimeter is flow measurement instruments which use a converging section of pipe to give an increase in the flow velocity and a corresponding pressure drop from which the flow rate can be deduced. They have been in common use for many years, especially in the water supply industry. It can be used in any position of pipe.

S6. Ans(d)
Sol. For fluidity measurement, the molten metal is made to flow along a channel at room temperature. The distance of metal flow before it solidifies and stops is a measure of its fluidity.

S7. Ans(c)
Sol. Cementite or iron carbide is an intermetallic compound of iron and carbon, more precisely an intermediate transition metal carbide with the formula Fe_3 C. It is a hard, brittle material. Cementite properties increases with increase amount of carbon

S8. Ans(b)
Sol. Concentric helical springs consists two or more springs placed inside one another having same axis and wound with opposite hand helices to avoid binding of adjacent coils.

S9. Ans(d)
Sol. wear is erosion or sideways displacement of material from its “derivative” and original position on a solid surface performed by the action of another surface and hardness is defined as the ability of a material to resist plastic deformation.

S10. Ans(a)
Sol. centrifugal force pushes the car outwards. Since the centre of mass of the car is above the level of the wheels, it tends to create a moment which pushes the outer wheels down and the inner wheels up. Since the outer wheels are being pushed downwards, the ground exerts a greater normal force on the outer wheels.