Multiple choice question for engineering
Set 1
1. Mechanical advantage is the ratio of effort to load.
a) True
b) False
Answer
Answer: b [Reason:] Mechanical advantage is the ratio of load to effort.
2. Leverage is the ratio of load arm to effort arm.
a) True
b) False
Answer
Answer: b [Reason:] Leverage is the ratio of effort arm to load arm.
3. The distance between fulcrum and dead weights is 100mm. Dead weights are of 2945.2N. An effort of 294.52N acts on the other hand. Find the distance between the fulcrum and other end of the lever.
a) 1000mm
b) 100mm
c) 10mm
d) 10000mm
Answer
Answer: b [Reason:] F ₂xl₂ =F₁ xl₁.
4. A right angled bell-crank is designed to raise a load of 5kN at short arm whose length is 100mm. Longer arm is of length 500mm. Calculate the reaction or force acting on the fulcrum.
a) 5.1
b) 5.8
c) 6.1
d) 6.8
Answer
Answer: a [Reason:] Force required for raising at longer end is found by F ₂xl₂ =F₁ xl₁. Reaction at fulcrum is
√ (F₁²+F₂²) as the two forces are perpendicular.
5. A right angled bell-crank is designed to raise a load of 5kN at short arm whose length is 100mm. Also longer arm is of length 500mm. If permissible bearing pressure on pin is 10N/mm² and diameter of the 20mm, find the length of the pin.
a) 35.5mm
b) 25.5mm
c) 20mm
d) 30mm
Answer
Answer: b [Reason:] R=p x d x L. Here R=√ (F₁²+F₂²).
6. A right angled bell-crank is designed to raise a load of 5kN at short arm whose length is 100mm. Also longer arm is of length 500mm. If permissible bearing pressure on pin is 10N/mm² and diameter of the 20mm, find the shear stress in the pin.
a) 8.12
b) 8.51
c) 9.12
d) 9.51
Answer
Answer: a [Reason:] τ=R/(2 x π x d²/4) as the pin is subjected to double shear. Also R=√ (F₁²+F₂²) and F ₂xl₂ =F₁ xl₁.
7. How many classes of levers are there?
a) 2
b) 3
c) 4
d) 5
Answer
Answer: b [Reason:] The three classes are Fulcrum in the middle, Resistance in the middle and Effort in the middle.
8. A bottle opener belongs to which class of the levers.
a) Effort in the middle
b) Fulcrum in the middle
c) Resistance in the middle
d) None of the mentioned
Answer
Answer: c [Reason:] In a bottle opener fulcrum can be considered at the end and resistance in middle as the actual work is done on the bottle cap which lies in middle of opener.
9. Fulcrum can be located at one end of the lever.
a) True
b) False
Answer
Answer: a [Reason:] Fulcrum can be located in middle or at one end of the lever.
Set 2
1. Ductile cast iron is
a) Also called nodular cast iron
b) Also called spheroidal graphite cast iron
c) Carbon is present in form of spherical nodules
d) All of the mentioned
Answer
Answer: d [Reason:] Ductile cast iron, also called as nodular cast iron or spheroidal cast iron consists of carbon in the form of spherical nodules in a ductile matrix.
2. Grey Cast iron is formed when
a) Carbon content in the alloy exceeds the amount that can be dissolved
b) Carbon content in the alloy is less than the amount that can be dissolved
c) Carbon content in the alloy is equal to the amount that can be dissolved in the alloy
d) None of the mentioned
Answer
Answer: a [Reason:] Grey Cast iron is formed only when carbon is present exceeds the solving capacity.
3. White cast iron is formed when
a) Graphite flakes are formed
b) Most of the carbon content in the alloy forms iron carbide
c) No iron carbide is formed
d) None of the mentioned
Answer
Answer: b [Reason:] :White cast iron is formed when most carbon in alloy forms iron carbide and there are no graphite flakes.
4. The term high alloy steels is used for alloy steels containing more than ___ of alloying elements.
a) 10%
b) 20%
c) 50%
d) 70%
Answer
Answer: a [Reason:] The term high alloy steels is used when alloying elements exceed 10%.Low and medium alloy steels are those when this figure is less than 10%.
5. Which of the following are true about low carbon steels?
a) Carbon content < 0.3%
b) Also called as mild steel
c) Are soft and ductile
d) All of the mentioned
Answer
Answer: d [Reason:] Low carbon steels contain carbon <0.3%. Because of low carbon, it is soft and ductile.
6. Which of the following are true for high carbon steels?
a) Carbon content=0.4%
b) Respond readily to heat treatments
c) Have much ductility as compared to low and medium carbon steels
d) Easy to weld
Answer
Answer: b [Reason:] High carbon steel have carbon % >0.5 and hence have less ductility. They are difficult to weld.
7. Which of the following are true?
a) 7C4 grade steel is more ductile than 10C4
b) Yield strength of 40C8 is greater than of 30C8
c) Hardness of 30C8 is greater than of 40C8
d) None of the mentioned
Answer
Answer: a [Reason:] The number before “C” indicates measure of carbon. Hence a) is true as higher the carbon, lower the ductility.
8. In the designation “xCb” which of the following are true?
a) x indicates 100 times the average % of carbon
b) b indicates 100 times the average percentage of manganese
c) x indicates 10 times the average percentage of carbon while b indicates 100 times the average percentage of manganese
d) b indicates 100 times the average % of carbon
Answer
Answer: a [Reason:] X indicates 100 times carbon % and b indicates 10 times manganese %.
9. Which of the steel in given options is best suited for auto mobile bodies and hoods?
a) 7C4
b) 10C4
c) 30C8
d) 40C8
Answer
Answer: a [Reason:] For automobile application like manufacturing bodies, ductile material is preferred.
10. Which of the following steel given in options respond fastest and easily to heat treatment?
a) 7C4
b) 10C4
c) 30C8
d) 40C8
Answer
Answer: d [Reason:] Alloys with higher carbon % respond willingly to heat treatment.
11. Which of the following given steels is popular with the name of machinery steel?
a) Low carbon steel
b) Medium carbon steel
c) High carbon steel
d) None of these
Answer
Answer: b [Reason:] It has ductility and can be heat treated easier than low carbon steel.
Set 3
1. The normal stress is perpendicular to the area under considerations, while the shear stress acts over the area.
a) True
b) False
Answer
Answer: a [Reason:] This is the convention used.
2. If a body is subjected to stresses in xy plane with stresses of 60N/mm² and 80N/mm² acting along x and y axes respectively. Also the shear stress acting is 20N/mm²Find the maximum amount of shear stress to which the body is subjected.
a) 22.4mm
b) 25mm
c) 26.3mm
d) 27.2mm
Answer
Answer: a [Reason:] τ(max)=√( [σ(x)-σ(y) ]²/2² + τ²).
3. If a body is subjected to stresses in xy plane with stresses of 60N/mm² and 80N/mm² acting along x and y axes respectively. Also the shear stress acting is 10N/mm². Find the inclination of the plane in which shear stress is maximal.
a) 45’
b) 30’
c) 60’
d) 15’
Answer
Answer: a [Reason:] tan (2Ǿ)=2τ/[σ(x) – σ(y)].
4. If a body is subjected to stresses in xy plane with stresses of 60N/mm² and 80N/mm² acting along x and y axes respectively. Also the shear stress acting is 20N/mm². Find the maximum normal stress.
a) 90
b) 92.4
c) 94.2
d) 96
Answer
Answer: b [Reason:] σ=[σ(x) +σ(y)]/2 + √( [σ(x)-σ(y) ]²/2² + τ²).
5. If a body is subjected to stresses in xy plane with stresses of 60N/mm² and 80N/mm² acting along x and y axes respectively. Also the shear stress acting is 20N/mm². Find the minimum normal stress.
a) 45.4
b) 47.6
c) 48.2
d) 50.6
Answer
Answer: b [Reason:] σ=[σ(x) +σ(y)]/2 – √( [σ(x)-σ(y) ]²/2² + τ²).
6. If compressive yield stress and tensile yield stress are equivalent, then region of safety from maximum principal stress theory is of which shape?
a) Rectangle
b) Square
c) Circle
d) Ellipse
Answer
Answer: b [Reason:] The equation of four lines is given by σ1=± S(yt), σ2=±S(yc) Now given S(yt)=S(yc), hence the region of safety is of square shape.
7. Maximum Principal Stress Theory is not good for brittle materials.
a) True
b) False
Answer
Answer: b [Reason:] Experimental investigations have shown that maximum principle stress theory gives good results for brittle materials.
8. The region of safety in maximum shear stress theory contains which of the given shape
a) Hexagon
b) Rectangle
c) Square
d) None of the mentioned
Answer
Answer: a [Reason:] In maximum shear stress theory we have the following equations: σ1= ±S(yt)
σ2= ±S (yt), σ1 – σ2 =±S (yt) assuming S(yt)=S(yc).
9. The total strain energy for a unit cube subjected to three principal stresses is given by?
a) U= [(σέ) ₁ + (σέ) ₂+ (σέ) ₃]/3
b) U= [(σ₁²+σ₂²+σ₃²)/2E] – (σ₁σ₂+σ₂σ₃+σ₃σ₁)2μ
c) U= [(σέ) ₁ + (σέ) ₂+ (σέ) ₃]/4
d) None of the mentioned
Answer
Answer: b [Reason:] U= [(σέ) ₁ + (σέ) ₂+ (σέ) ₃]/2 is the basic formula. After substituting values of έ₁, έ₂ and έ₃, we get the expression b.
10. Distortion energy theory is slightly liberal as compared to maximum shear stress theory.
a) True
b) False
Answer
Answer: a [Reason:] The hexagon of maximum shear theory falls completely inside the ellipse of distortion energy theorem.
Set 4
1. Which of the following isn’t a main part of rivet?
a) Head
b) Shank
c) Point
d) Thread
Answer
Answer: d [Reason:] There aren’t any threads in rivets.
2. A rivet is specified as a 20mm rivet. What does it mean?
a) None of the mentioned
b) Shank dia 20mm
c) Head dia 20mm
d) Both head and shank dia 20mm
Answer
Answer: b [Reason:] Terminology is this way.
3. In hand riveting die is a part of hammer.
a) True
b) False
Answer
Answer: b [Reason:] Die is a part of hammer in machine riveting.
4. In hot riveting the shank portion is subjected to compressive stress.
a) True
b) False
Answer
Answer: b [Reason:] It is subjected to tensile stress as the head rests against the connected members to prevent reduction in length.
5. The amount by which the two rods to be joined are drawn together is called as?
a) Draw
b) Portray
c) Lead
d) Pitch
Answer
Answer: a [Reason:] Draw measures the amount of distance advancing after which spigot rests on socket.
6. Two steel rods connected by cotter joint are subjected to 50 kN load each. What is the minimum diameter required of the rods? (Given: Yielding Stress= 400N/mm² ; Factor of Safety=6)
a) 31mm
b) 35mm
c) 36mm
d) 40mm
Answer
Answer: a [Reason:] d=√(4P/πσ) where σ= Yielding Stress/F.S ; d=30.90mm or 31 mm.
7. Among punching and drilling, which is cheaper?
a) Punching
b) Drilling
c) Equally expensive
d) Cannot be determined
Answer
Answer: a [Reason:] Drilling has more accuracy and is more expensive.
8. Among punching and drilling, punching is safer.
a) True
b) False
Answer
Answer: b [Reason:] Punching injures the metal in the vicinity of the hole.
9. Riveting is not recommended for aluminium alloys.
a) True
b) False
Answer
Answer: b [Reason:] Aluminium alloys have poor weldability and hence riveting is preferred.
10. In joining steel plate and asbestos, welding is preferred over riveting.
a) True
b) False
Answer
Answer: b [Reason:] Riveting is preferred in joining heterogeneous materials.
11. Quality checking of riveted joint is much expensive than that of welded joint.
a) True
b) False
Answer
Answer: b [Reason:] In welding, inspections like radiographic inspections are quite costly.
Set 5
1. A power screw is only used to convert rotary motion into linear motion and not for transmitting power.
a) True
b) False
Answer
Answer: b [Reason:] Power screw converts the motion from rotary to linear and is used for power transmission.
2. Depending upon the holding arrangement, power screws operate in how many different arrangements.
a) 2
b) 3
c) 4
d) 5
Answer
Answer: a [Reason:] There are two types of arrangements. In one screw rotates while nut remains stationary and vice versa.
3. A power screw has no problem of wear as there is very less amount of friction associated.
a) True
b) False
Answer
Answer: b [Reason:] Wear is a serious problem in power screws as there is high friction in threads.
4. V threads are highly recommended for fastening as well as power transmission purpose.
a) Yes
b) Never
c) In some cases
d) Can’t be stated
Answer
Answer: b [Reason:] In fastening, high frictional force is required and hence V threads are used whereas in power transmission, reduction in frictional forces is required.
5. Trapezoidal threads are better than square threads as there is radial pressure or side thrust on the nut.
a) True
b) False
Answer
Answer: b [Reason:] Trapezoidal and not square threads suffer from the problem of bursting.
6. Trapezoidal threads screws have less load carrying capacity as compared to square thread screws.
a) True
b) False
Answer
Answer: b [Reason:] Square threads have less thickness at the core diameter and hence lower load carrying capacity.
7. Which of the following are true for buttress threads?
a) Combination of square and trapezoidal threads
b) Transmit motion in one direction only
c) They are used in vices
d) All of the mentioned
Answer
Answer: d [Reason:] As force is applied only in one direction in a vice so buttress threads are used.
8. Tr 40 x 14(P 7), here 14 indicates
a) Pitch
b) Lead
c) Diameter
d) None of the mentioned
Answer
Answer: b [Reason:] Tr=Trapezoidal threads,14=Lead(mm),7=Pitch(mm).
9. Nominal diameter of the screw thread is the same as core diameter.
a) True
b) False
Answer
Answer: b [Reason:] Nominal diameter is the largest diameter while core diameter is the smallest diameter of the screw thread.
10. If nominal diameter of screw thread=50mm and pitch=10mm then the mean diameter of the screw thread will be?
a) 40mm
b) 45mm
c) 60mm
d) 55mm
Answer
Answer: b [Reason:] Diameter(mean)=Diameter(nominal) – 0.5P .
11. If the load itself begin to the screw and descend down, unless a restraining torque is applied then the condition is termed as
a) Halting
b) Overhaulting
c) Front driving
d) None of the mentioned
Answer
Answer: b [Reason:] Overhaulting is the condition when load itsel begin to turn the screw.
12. Self-locking takes place when
a) Coefficient of friction is equal to or greater than the tangent of the helix angle
b) Coefficient of friction is lesser than or equal to the tangent of the helix angle
c) Coefficient of friction is equal to or greater than the tangent of the helix angle
d) None of the mentioned
Answer
Answer: c [Reason:] Self locking takes place if load does not descend on its own and that is possible only in c condition.