**SSC Junior Engineer Exam Paper – 2017 “held on 01 March 2017 “Morning Shift (Mechanical Engineering) **

** **

**Q 1:** The ratio (Surface convection resistance)/(internal conduction resistance)_____

**Options:**

**1**) Grashoff number

**2**) Biot number

**3**) Stanton number

**4**) Prandtl number

**Answer:** Biot number

** **

**Q 2:** An ideal air compressor cycle (with clearance) on p-v diagram can be represented by ________ processes.

**Options:**

**1**) one adiabatic, two isobaric, and one constant volume

**2**) two adiabatic and two isobaric

**3**) two adiabatic, one isobaric, and one constant volume

**4**) one adiabatic, one isobaric, and two constant volume

**Answer:** two adiabatic and two isobaric

** **

**Q3:** In a shell and tube heat exchanger, baffles are provided on the shell side to ______.

**Options:**

**1**) Prevent the stagnation of shell side fluid

**2**) Improve heat transfer

**3**) Provide support for tubes

**4**) All options are correct

**Answer:** All options are correct

** **

**Q 4:** The ratio of the thickness of thermal boundary layer to the thickness of hydrodynamic boundary layer is equal to (Prandtl number)n, where n is______.

**Options:**

**1**) – 1/3

**2**) – 2/3

**3**) 1

**4**) – 1

**Answer:** – 1/3

** **

**Q 5:** In regarding nucleate boiling _______.

**Options:**

**1**) The temperature of the surface is greater than the saturation temperature of the liquid

**2**) Bubbles are created by expansion of entrapped gas or vapour at small cavities in the surface

**3**) The temperature is greater than that of film boiling

**4**) All options are correct

**Answer:** The temperature is greater than that of film boiling

** **

**Q 6:** Boundary layer is defined as ______.

**Options:**

**1**) A thin layer at the surface where gradients of both velocity and temperature are small

**2**) A thin layer at the surface where velocity and velocity gradients are large

**3**) A thick layer at the surface where velocity and temperature gradients are large

**4**) A thin layer at the surface where gradients of both velocity and temperature are large

**Answer:** A thin layer at the surface where gradients of both velocity and temperature are large

** **

**Q 7: **Two insulating materials of thermal conductivity K and 2K are available for lagging a pipe carrying a hot fluid. If the radial thickness of each material is the same _____.

**Options:**

**1**) Material with higher thermal conductivity should be used for the inner layer and one with layer and one with lower thermal conductivity for the outer

**2**) Material with lower thermal conductivity should be used for the inner layer and one with higher thermal conductivity for the outer

**3**) It is immaterial in which sequence the insulating materials are used

**4**) None of these

**Answer:** Material with lower thermal conductivity should be used for the inner layer and one with higher thermal conductivity for the outer

** **

**Q 8:** Critical thickness of insulation for spheres is given by _____.

**Options:**

**1**) k/h

**2**) k/4h

**3**) h/2k

**4**) 2k/h

**Answer:** 2k/h

** **

**Q 9:** Which surface will have the least emissivity ?

**Options:**

**1**) Smooth glass

**2**) Plaster

**3**) Aluminium foil

**4**) Concrete

**Answer:** Aluminium foil

** **

**Q 10:** The process of heat transfer from one particle of the body to another without the actual motion of the particle, is known as ______ .

**Options:**

**1**) Conduction

**2**) Convection

**3**) Radiation

**4**) All options are correct

**Answer:** Conduction

** **

**Q 11: **The process of heat transfer from a hot body to a cold body in a straight line, without affecting the intervening medium, is known as ______.

**Options:**

**1**) Conduction

**2**) Convection

**3**) Radiation

**4**) All options are correct

**Answer:** Radiation

** **

**Q 12:** Heat is transferred from an electric bulb by ______.

**Options:**

**1**) Conduction

**2**) Convection

**3**) Radiation

**4**) All options are correct

**Answer:** Radiation

** **

**Q 13:** Assumption made in the Fourier’s law is that the heat flow

A. Is in steady state

B. Through a solid medium in one dimension

**Options:**

**1**) Only (A)

**2**) Only (B)

**3**) Both (A) and (B)

**4**) None of these

**Answer:** Both (A) and (B)

** **

**Q 14:** If thermal conductivity of a material of wall varies as K_0 (1 + αt), then the temperature at the centre of the wall as compared to that in case of constant thermal conductivity, will be ______.

**Options:**

**1**) More

**2**) Less

**3**) Same

**4**) Depend on other factors

**Answer:** More

** **

**Q 15:** With increase in temperature, thermal conductivity of air ______.

**Options:**

**1**) Increases

**2**) Decreases

**3**) Remains the same

**4**) None of these

**Answer:** Increases

** **

**Q 16:** Liquid metal having highest thermal conductivity is of _______.

**Options:**

**1**) Sodium

**2**) Potassium

**3**) Lead

**4**) Mercury

**Answer:** Sodium

**Candidate Answer:** Mercury

** **

**Q 17:** Minimum thermal diffusivity is of ______.

**Options:**

**1**) Aluminium

**2**) Rubber

**3**) Iron

**4**) Lead

**Answer:** Rubber

** **

**Q 18:** Critical radius of a hollow cylinder is defined as _______.

**Options:**

**1**) Outer radius which gives maximum heat flow

**2**) Outer radius which gives minimum heat flow

**3**) Inner radius which gives minimum heat flow

**4**) Inner radius which gives maximum heat flow

**Answer:** Outer radius which gives maximum heat flow

** **

**Q 19:** Heat exchangers are used in

- Condensers and boilers in steam plants

B. Radiators

C. Intercoolers and preheaters

D. Condensers and evaporators in refrigerators and air conditioners

**Options:**

**1**) Only A

**2**) Only B

**3**) Only C

**4**) A, B, C and D

**Answer:** A, B, C and D

** **

**Q 20:** Automobile radiator is a heat exchanger of _____ type.

**Options:**

**1**) Counter flow

**2**) Parallel flow

**3**) Cross flow

**4**) Regenerator

**Answer:** Cross flow

** **

**Q 21: **For a closed system, difference between the heat added to the system and work done by the gas, is equal to the change in_____.

**Options:**

**1**) Enthalpy

**2**) Entropy

**3**) Internal energy

**4**) Temperature

**Answer:** Internal energy

** **

**Q 22:** The sequence of process that eventually returns the working substance to its original state, is known as ______.

**Options:**

**1**) Event

**2**) Thermodynamic cycle

**3**) Thermodynamic property

**4**) None of these

**Answer:** Thermodynamic cycle

** **

**Q 23:** According to Kelvin-Plank’s statement, a perpetual motion machine of _______.

**Options:**

**1**) First kind is possible

**2**) First kind is impossible

**3**) Second kind is impossible

**4**) Second kind is possible

**Answer:** Second kind is impossible

** **

**Q 24:** According to kinetic theory of gases, at absolute zero ______.

**Options:**

**1**) Specific heat of molecules reduces to zero

**2**) Kinetic energy of molecules reduces to zero

**3**) Volume of gas reduce to zero

**4**) Pressure of gas reduce to zero

**Answer:** Kinetic energy of molecules reduces to zero

** **

**Q 25:** According to Gay-Lussac’s law for perfect gases, the absolute pressure of given mass varies directly as _______.

**Options:**

**1**) Temperature

**2**) Absolute temperature

**3**) Absolute temperature, if volume remains constant

**4**) Product of absolute temperature and volume

**Answer:** Absolute temperature, if volume remains constant

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**Q 26:** Three states of matter are distinguished with respect to molecules by the ______.

**Options:**

**1**) Atoms in molecules

**2**) Number

**3**) Orientation

**4**) Character of motion

**Answer:** Character of motion

** **

**Q 27: **Equal volume of all gases, at the same temperature and pressure, contain equal number of molecules. This is according to _______.

**Options:**

**1**) Charle’s law

**2**) Avagardo’s law

**3**) Joule’s law

**4**) Gay Lussac law

**Answer:** Avagardo’s law

** **

**Q 28:**Specific heat of a gas, Cp = Cv, at

**Options:**

**1**) Absolute zero

**2**) Critical temperature

**3**) Triple point

**4**) All temperatures

**Answer:** Absolute zero

** **

**Q 29:** The specific heat at constant volume of solids obeys Debye’s T3 law at ______.

**Options:**

**1**) High temperatures

**2**) Low temperatures

**3**) High pressures

**4**) All temperatures

**Answer:** All temperatures

** **

**Q 30:** A reversible process _____.

**Options:**

**1**) Must pass through a continuous series of equilibrium states

**2**) Leaves no history of the events in surroundings

**3**) Must pass through the same states on the reversed path as on the forward path

**4**) All options are correct

**Answer:** All options are correct

** **

**Q 31:** In Red Wood Viscometer ______.

**Options:**

**1**) Absolute value of viscosity is determined

**2**) Part of the head of fluid is utilised in overcoming friction

**3**) Fluid discharges through orifice with negligible velocity

**4**) Comparison of viscosity is done

**Answer:** Absolute value of viscosity is determined

** **

**Q 32:** A rotameter is a device used to measure ______.

**Options:**

**1**) Velocity of fluid in pipes

**2**) Velocity of gauges

**3**) Votex flow

**4**) Flow of fluids

**Answer:** Flow of fluids

** **

**Q 33: **Steady flow occurs when ______.

**Options:**

**1**) Pressure does not change along the flow

**2**) Velocity does not change

**3**) Conditions change gradually with time

**4**) Conditions do not change with time at any point

**Answer:** Conditions do not change with time at any point

** **

**Q 34: **If the particles of a fluid attain such velocities that vary from point to point in magnitude and direction as well as from instant, the flow is _______.

**Options:**

**1**) Uniform flow

**2**) Steady flow

**3**) Turbulent flow

**4**) Laminar flow

**Answer:** Turbulent flow

** **

**Q 35:** Flow occurring in a pipeline when a valve is being opened is ______.

**Options:**

**1**) Steady

**2**) Unsteady

**3**) Laminar

**4**) Vortex

**Answer:** Unsteady

** **

**Q 36:** For measuring flow by a Venturimeter, it should be installed in _______.

**Options:**

**1**) Vertical line

**2**) Horizontal line

**3**) Inclined line with upward flow

**4**) In any direction and in any location

**Answer:** In any direction and in any location

** **

**Q 37:** A streamline is defined as the line ______.

**Options:**

**1**) Parallel to central axis flow

**2**) Parallel to outer surface to pipe

**3**) Of equal velocity in a flow

**4**) Along with the pressure drop is uniform

**Answer:** Of equal velocity in a flow

** **

**Q 38:** The purpose of surge tank in a pipe line is to _______.

**Options:**

**1**) Smoothen the flow of water

**2**) Compensate friction losses in pipe

**3**) Prevent occurrence of hydraulic jump

**4**) Relieve pressure due to water hammer

**Answer:** Compensate friction losses in pipe

** **

**Q 39:** The resultant upward pressure of a fluid on a floating body is equal to the weight of fluid displaced by the body. This definition is according to _______.

**Options:**

**1**) Buoyancy

**2**) Equilibrium of a floating body

**3**) Archimedes’ principle

**4**) Bernoulli’s theorem

**Answer:** Buoyancy

** **

**Q 40:** A balloon lifting in air follows the ______.

**Options:**

**1**) Law of gravitation

**2**) Archimedes principle

**3**) Principle of buoyancy

**4**) All options are correct

**Answer:** All options are correct

** **

**Q 41:** Hydraulic grade line as compared to the centre line of conduct ______.

**Options:**

**1**) Should be always above

**2**) Should be always below

**3**) Should always be parallel

**4**) May be above or below

**Answer:** Should be always above

** **

**Q 42:** A Piezometer cannot be used for pressure measurement in pipes when _______.

**Options:**

**1**) Pressure difference is low

**2**) Velocity is high

**3**) Fluid in the pipe is a gas

**4**) Fluid is highly viscous

**Answer:** Fluid in the pipe is a gas

** **

**Q 43:** A Hot Wire Anemometer is used for the measurement of ______.

**Options:**

**1**) Pressure of gases

**2**) Velocity of gases

**3**) Viscosity of gases

**4**) Viscosity of liquids

**Answer:** Velocity of gases

** **

**Q 44:** Friction drag is generally larger than the pressure drag in _______.

**Options:**

**1**) Flow past a sphere

**2**) Flow past a cylinder

**3**) Flow past an airfoil

**4**) Flow past a thin sheet

**Answer:** Flow past a cylinder

** **

**Q 45: **If one of the wall moves in the direction of flow with uniform velocity while the other wall is stationary, then the resulting flow between parallel walls is called ______.

**Options:**

**1**) Plug flow

**2**) Stoke’s flow

**3**) Couette flow

**4**) Euler’s flow

**Answer:** Plug flow

** **

**Q 46:** The ratio of the energy absorbed by the body to total energy falling on it is called _____.

**Options:**

**1**) absorptive power

**2**) emissive power

**3**) emissivity

**4**) None of these

**Answer:** absorptive power

** **

**Q 47: **In a flow field, at the stagnation point _______.

**Options:**

**1**) Pressure is zero

**2**) velocity of fluid is zero

**3**) Pressure head is equal to velocity

**4**) All the velocity head is converted into pressure head

**Answer:** velocity of fluid is zero

** **

**Q 48:** Viscosity is the most important property in the ______.

**Options:**

**1**) Travel of a bullet through air

**2**) Water jet issuing from a fire air

**3**) Formation of soap bubbles

**4**) Flow of castor oil through a tube

**Answer:** Formation of soap bubbles

** **

**Q 49:** If pressure at any point in the liquid approaches the vapor pressure, liquid starts vaporising and creates pockets or bubbles of dissolved gases and vapours. This phenomenon is ______.

**Options:**

**1**) Surface tension

**2**) Adhesion

**3**) Vaporisation

**4**) Cavitation

**Answer:** Surface tension

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** **

**Q 50:** The fluid forces considered in the Navier-Strokes equation are ______.

**Options:**

**1**) Gravity, pressure and viscous

**2**) Gravity, pressure and turbulent

**3**) Pressure, viscous and turbulent

**4**) Gravity, viscous and turbulent

**Answer:** Gravity, pressure and viscous

** **

**Q 51:** Hydraulic grade line for any flow system as compared to energy line is ______.

**Options:**

**1**) Above

**2**) Below

**3**) At same level

**4**) Uncertain

** **

**Answer:** Below

**Q 52:** To avoid vaporisation in the pipe line, the pipe line over the ridge is laid such that it is not more than _____.

**Options:**

**1**) 2.4 m above the hydraulic gradient

**2**) 6.4m above the hydraulic gradient

**3**) 10.0 m above the hydraulic gradient

**4**) 5.0 m above the hydraulic gradient

**Answer:** 2.4 m above the hydraulic gradient

** **

**Q 53:** The locus of elevations that water will rise in a series of pitot tube is called ______.

**Options:**

**1**) Hydraulic grade line

**2**) Pressure head

**3**) Energy grade line

**4**) Head loss

**Answer:** Energy grade line

** **

**Q 54:** Pressure in Pascals at a depth of 1 m below the free surface of a body of water will be equal to _______.

**Options:**

**1**) 1 Pa

**2**) 98.1 Pa

**3**) 981 Pa

**4**) 9810 Pa

**Answer:** 9810 Pa

** **

**Q 55: **Water flows up a tapered pipe as shown in the figure. What is the magnitude of the deflection h of the differential mercury manometer corresponding to 126 L/s ?

The friction in the pipe can be completely neglected.

**Options:**

**1**) 16.28 cm

**2**) 17.28 cm

**3**) 19.28 cm

**4**) 25.28 cm

**Answer:** 19.28 cm

** **

**Q 56:** If a pump is handling water and is discharging a certain flow Q at a constant total dynamic head requiring a definite B.H.P., the same pump when handling a liquid of specific gravity 0.75 and viscosity nearly same as of water would discharge

**Options:**

**1**) same quantity of liquid

**2**) 0.75Q

**3**) Q/0.75

**4**) 1.5Q

**Answer:** same quantity of liquid

** **

**Q 57:** A 20 cm diameter pipe 5000 metres long conveys 0.05 cumec of water which is to be pumped through a height of 6 metres. What is the horse power required by the pump, if its efficiency is 75 %? (take 4f = 0.006)

**Options:**

**1**) 74.2 HP

**2**) 74 HP

**3**) 75 HP

**4**) 50 HP

**Answer:** 74.2 HP

** **

**Q 58:** For laminar flow in a pipe, V is equal to

**Options:**

**1**) Umax

**2**) 0.5 Umax

**3**) 0.25 Umax

**4**) 2 Umax

**Answer:** 0.5 Umax

** **

**Q 59:** Water at 20° C flowing through a 20 cm diameter pipe. Take kinematic viscosity of water at 20°C is equal to 0.0101 stoke. Assume that the changes from laminar to turbulent at Re = 2320. The critical velocity will be _____.

**Options:**

**1**) 1.117 cm/sec

**2**) 11.17 cm/sec

**3**) 111.7 cm/sec

**4**) 1.117 m/sec

**Answer:** 1.117 cm/sec

** **

**Q 60:** Surge wave is an example of _____.

**Options:**

**1**) Steady uniform flow

**2**) Steady non-uniform flow

**3**) Unsteady uniform flow

**4**) Unsteady non-uniform flow

**Answer:** Unsteady non-uniform flow

** **

**Q 61:** Quick return mechanism is an inversion of _____.

**Options:**

**1**) Four bar chain

**2**) Single slider crank chain

**3**) Double slider crank chain

**4**) Crossed slider crank chain

**Answer:** Single slider crank chain

** **

**Q 62:** In gears, interference takes place when _____.

**Options:**

**1**) Tip of a tooth of a mating gear digs into the portion between base and root circles

**2**) Gears do not move smoothly in the absence of lubrication

**3**) Pitch of the gear is not same

**4**) Gear teeth are undercut

**Answer:** Tip of a tooth of a mating gear digs into the portion between base and root circles

** **

**Q 63:** In a multiple V belt drive, when a single belt is damaged, it is preferable to change the complete set to _____.

**Options:**

**1**) Reduce vibration

**2**) Reduce slip

**3**) Ensure uniform loading

**4**) Ensure proper alignment

**Answer:** Ensure proper alignment

** **

**Q 64:** The centre of gravity of the coupler link in a 4-bar mechanism would experience _____.

**Options:**

**1**) No acceleration

**2**) Only linear acceleration

**3**) Only angular acceleration

**4**) Both linear and angular accelerations

**Answer:** Both linear and angular accelerations

** **

**Q 65:** The amplitude of underdamping a small damping varies with time as _____.

**Options:**

**1**) Linearly

**2**) Arithmetically

**3**) Geometrically

**4**) Exponentially

**Answer:** Exponentially

** **

**Q 66:** Whirling speed of a shaft coincide with the natural frequency of the _____.

**Options:**

**1**) Longitudinal vibration

**2**) Transverse vibration

**3**) Torsional vibration

**4**) Coupled between torsional vibration

**Answer:** Transverse vibration

** **

**Q 67:** A mass of 1 kg is attached to the end of a spring with stiffness 0.7 N/mm. The critical damping coefficient of this system is ____.

**Options:**

**1**) 1.40 Ns/m

**2**) 18.522 Ns/m

**3**) 52.92 Ns/m

**4**) 529.20 Ns/m

**Answer:** 52.92 Ns/m

** **

**Q 68:** Rankine’s theory of failure is applicable for which of the following type of materials?

**Options:**

**1**) Brittle

**2**) Ductile

**3**) Elastic

**4**) Plastic

**Answer:** Brittle

** **

**Q 69:** The shock absorbing capacity of a bolt can be increased by _____.

**Options:**

**1**) Tightening it properly

**2**) Increasing shank diameter

**3**) Grinding the shank

**4**) Using washer

**Answer:** Grinding the shank

** **

**Q 70:** Which if the following key is under compression rather than in being shear when under load?

**Options:**

**1**) Saddle

**2**) Barth

**3**) Feather

**4**) Kennedy

**Answer:** Barth

** **

**Q 71:** Shaft is subjected to which of the following stresses?

**Options:**

**1**) Bending

**2**) Torsional

**3**) Both bending and torsional

**4**) None of these

**Answer:** Both bending and torsional

** **

**Q 72:** Which of the following is self-aligning bearing?

**Options:**

**1**) Conical

**2**) Spherical

**3**) Rectangular

**4**) None of these

**Answer:** Spherical

** **

**Q 73:** Which of the following is Trapezoidal thread?

**Options:**

**1**) Acme

**2**) Square

**3**) Buttress

**4**) All options are correct

**Answer:** Acme

** **

**Q 74:** The efficiency of self-locking screw is _____.

**Options:**

**1**) More than 50%

**2**) Less than 50%

**3**) Equal to 50%

**4**) None of these

**Answer:** Less than 50%

** **

**Q 75:** The most suitable bearing for carrying very heavy loads with slow speed is _____.

**Options:**

**1**) Hydrodynamic bearing

**2**) Ball bearing

**3**) Roller bearing

**4**) Hydrostatic bearing

**Answer:** Hydrostatic bearing

** **

**Q 76:** The outside diameter of a hollow shaft is twice it’s inside diameter. The ratio of its torque carrying capacity to that of a solid shaft of the same material and the same outside diameter is _____

**Options:**

**1**) 15/16

**2**) 3/4

**3**) 1/2

**4**) 1/16

**Answer:** 15/16

** **

**Q 77:** A solid shaft can resist a bending moment of 3 kNm and a twisting moment of 4 kNm together, then the maximum torque that can be applied is _____.

**Options:**

**1**) 7.0 kNm

**2**) 3.5 kNm

**3**) 4.5 kNm

**4**) 5.0 kNm

**Answer:** 5.0 kNm

** **

**Q 78:** Under torsion, brittle materials generally fail ______.

**Options:**

**1**) Along a plane perpendicular to its longitudinal axis

**2**) In the direction of minimum tension

**3**) Along surfaces forming a 45° angle with the longitudinal axis

**4**) Not in any specific manner

**Answer:** Along surfaces forming a 45° angle with the longitudinal axis

** **

**Q 79:** The shear stress distribution over a rectangular cross-section of a beam follows _____.

**Options:**

**1**) A straight line path

**2**) A circular path

**3**) A parabolic path

**4**) An elliptical path

**Answer:** A parabolic path

** **

**Q 80:** When two mutually perpendicular principal stresses are unequal but alike, the maximum shear stress is represented by _____.

**Options:**

**1**) The diameter of the Mohr’s circle

**2**) Half the diameter of the Mohr’s circle

**3**) One-third the diameter of the Mohr’s circle

**4**) One-fourth the diameter of the Mohr’s circle

**Answer:** Half the diameter of the Mohr’s circle

** **

**Q 81:** The plane of maximum shear stress has normal stress that is _____.

**Options:**

**1**) Maximum

**2**) Minimum

**3**) Zero

**4**) None of these

**Answer:** Zero

** **

**Q 82:** Consider the following theories of failure:

A. Maximum stress theory

B. Maximum strain theory

C. Maximum shear stress theory

D. Maximum energy or distortion theory

The most suitable for ductile material i

**Options:**

**1**) A and B

**2**) A and C

**3**) A and D

**4**) C and D

**Answer:** C and D

** **

**Q 83:** For ductile materials, the most appropriate failure theory is _____.

**Options:**

**1**) Maximum shear stress theory

**2**) Maximum principal stress theory

**3**) Maximum principal strain theory

**4**) Shear strain energy theory

**Answer:** Maximum shear stress theory

** **

**Q 84:** All the failure theories give nearly the same result _____.

**Options:**

**1**) When one of the principal stresses at a point is larger in comparison to the other

**2**) When shear stresses act

**3**) When both the principal stresses are numerically equal

**4**) For all situations of stress

**Answer:** When one of the principal stresses at a point is larger in comparison to the other

** **

**Q 85:** From the hypothesis given by Rankine, the criteria for failure of brittle material is _____.

**Options:**

**1**) Maximum principal stress

**2**) Maximum strain energy

**3**) Maximum shear stress

**4**) Maximum shear strain energy

**Answer:** Maximum principal stress

** **

**Q 86:** In a closed helical spring subjected to an axial load, other quantities remaining the same, if the wire diameter is doubled and mean radius of the coil is also doubled, then stiffness of spring when compared to original one will become _____.

**Options:**

**1**) Twice

**2**) Four times

**3**) Eight times

**4**) Sixteen times

**Answer:** Twice

** **

**Q 87:** The Poisson’s ratio for most of the materials is close to _____.

**Options:**

**1**) 1 : 2

**2**) 1 : 3

**3**) 1 : 4

**4**) 1 : 5

**Answer:** 1 : 3

** **

**Q 88:** True stress represents the ratio of _____.

**Options:**

**1**) Average load and average area

**2**) Average load and maximum area

**3**) Maximum load and maximum area

**4**) Instantaneous load and instantaneous area

**Answer:** Instantaneous load and instantaneous area

** **

**Q 89:** For an element under the effect of biaxial state of normal stress, the normal stresses are on a 45 ° plane is equal to _____.

**Options:**

**1**) Difference of normal stresses

**2**) Sum of normal stresses

**3**) Half of the sum of normal stresses

**4**) Half of the difference of normal stresses

**Answer:** Half of the sum of normal stresses

** **

**Q 90:** For a thin spherical shell subjected to internal pressure, the ratio of volumetric strain to diametrical strain is _____.

**Options:**

**1**) 5 : 4

**2**) 3 : 2

**3**) 2 : 1

**4**) 3 : 1

**Answer:** 3 : 1

** **

**Q 91:** Stud and projection welding belong to the following category of welding _____.

**Options:**

**1**) gas welding

**2**) arc welding

**3**) resistance welding

**4**) pressure welding

**Answer:** resistance welding

** **

**Q 92:** Electrode gets consumed in the following welding process _____.

**Options:**

**1**) gas

**2**) resistance

**3**) thermit

**4**) arc

**Answer:** arc

** **

**Q 93:** The strength of a properly welded joint as compared to base metal would be _____.

**Options:**

**1**) same

**2**) more

**3**) less

**4**) unpredictable

**Answer:** more

** **

**Q 94:** Oxygen to acetylene ratio in case of carburising flame is _____.

**Options:**

**1**) 0.5 : 1

**2**) 0.9 : 1

**3**) 1 : 1

**4**) 1 : 1.2

**Answer:** 0.9 : 1

** **

**Q 95:** For steel castings, the following type of sand is better _____.

**Options:**

**1**) fine-grain

**2**) coarser-grain

**3**) medium grain

**4**) fine-grain, coarser-grain and medium grain all are equally good

**Answer:** coarser-grain

** **

**Q 96:** Hot tear refers to _____.

**Options:**

**1**) casting defect

**2**) process of fabrication

**3**) process of heat treatment

**4**) weathering of non-ferrous materials

**Answer:** casting defect

** **

**Q 97:** Slick in a foundry shop is used to _____.

**Options:**

**1**) make and repair corners in a mould

**2**) thoroughly mix up moulding sand

**3**) make venting holes in the mould

**4**) prepare gates

**Answer:** make and repair corners in a mould

** **

**Q 98:** Which of the following processes would produce best components?

**Options:**

**1**) die casting

**2**) hot rolling

**3**) extrusion

**4**) forging

**Answer:** die casting

** **

**Q 99:** A sprue hole is _____.

**Options:**

**1**) a casting defect

**2**) a hold made for riveting

**3**) a blind hole in jigs

**4**) an opening in mould for pouring molten metal

**Answer:** an opening in mould for pouring molten metal

** **

**Q 100:** Coining is the operation of _____.

**Options:**

**1**) cold forging

**2**) hot forging

**3**) cold extrusion

**4**) piercing

**Answer:** cold forging