Sae IIT(Bhu) Quiz 1
-
The following figure depicts components of an engine. If the crank radius is R and stroke length (the distance between TDC and BDC) is S then find the relation between R and S.
-
S=2*R
-
S=R/2
-
S=4*R
-
S=R/4
-
SAE IIT(BHU) QUIZ 1 assesses knowledge on engine mechanics, covering crank mechanics, engine cycles, and component functions like flywheels and carburetors. It is designed for students and professionals in mechanical and automotive engineering.
Quiz Preview
- 2.
A four-stroke engine delivers an output of 1200 RPM from the crankshaft. What is the total number of power strokes provided by the engine in 1 second?
-
10
-
20
-
5
-
12
Correct Answer
A. 10Explanation
In a four-stroke engine, each revolution of the crankshaft consists of four strokes: intake, compression, power, and exhaust. Therefore, for every two revolutions of the crankshaft, there is one power stroke. Since the engine delivers an output of 1200 RPM (revolutions per minute), in one second it will complete 1200/60 = 20 revolutions. Therefore, the total number of power strokes provided by the engine in 1 second is 20/2 = 10.Rate this question:
-
- 3.
What is the function of the flywheel?
-
Improves traction with the surface on which the car is moving.
-
Balances the weight against the crank shaft.
-
Stores rotational energy generated by the engine.
-
It is a type of braking system used in automobiles.
Correct Answer
A. Stores rotational energy generated by the engine.Explanation
The flywheel in a car is responsible for storing the rotational energy generated by the engine. This stored energy helps to maintain a consistent and smooth rotation of the engine, especially during periods of low power output or when the engine is idling. It also helps to provide a reserve of energy that can be used to overcome any momentary increases in load or demand from the engine. Overall, the flywheel plays a crucial role in ensuring the efficient and reliable operation of the engine.Rate this question:
-
- 4.
Why is carburetor used in automobiles?
-
It is used to discharge fuel in petrol engines in an adequate quantity.
-
It is used to discharge fuel in Diesel engines in an adequate quantity.
-
It is used to prepare air-fuel mixture in a fixed ratio in petrol engines.
-
It is used to prepare air-fuel mixture in a fixed ratio in diesel engines.
Correct Answer
A. It is used to prepare air-fuel mixture in a fixed ratio in petrol engines.Explanation
Carburetors are used in automobiles to prepare the air-fuel mixture in a fixed ratio in petrol engines. This is necessary for the efficient combustion of fuel and to ensure that the engine runs smoothly. The carburetor mixes the fuel with the incoming air in the correct proportion and delivers it to the engine cylinders. This allows for better fuel efficiency and performance of the engine.Rate this question:
-
- 5.
Which of the following components control the motion of intake and exhaust valves?
-
Piston
-
Crankshaft
-
Camshaft
-
Flywheel
Correct Answer
A. CamshaftExplanation
The camshaft is responsible for controlling the motion of the intake and exhaust valves in an engine. It is a rotating shaft with specially shaped lobes that open and close the valves at the correct timing and duration. As the camshaft rotates, the lobes push against the valve lifters, which in turn open and close the valves. This allows the intake valves to let in air and fuel mixture and the exhaust valves to release the exhaust gases. The camshaft plays a crucial role in synchronizing the valve timing with the movement of the pistons, ensuring efficient combustion and power generation in the engine.Rate this question:
-
- 6.
Which engine delivers the maximum efficiency based on fuel among the following:
-
Two-stroke diesel engine
-
Two-stroke petrol engine
-
Four-stroke diesel engine
-
Four-stroke petrol engine
Correct Answer
A. Four-stroke diesel engineExplanation
The four-stroke diesel engine delivers maximum efficiency based on fuel compared to the other options listed. Diesel engines are generally more fuel-efficient than petrol engines due to their higher compression ratios and the fact that diesel fuel has a higher energy density. Additionally, the four-stroke cycle allows for better combustion efficiency and power output.Rate this question:
-
- 7.
There are two gears with radius R1 and R2 and the number of teeth N1 and N2 respectively. For no slip between the gears which of the following relations are true
-
R1/R2 = N1/N2
-
R1/R2 = N2/N1
-
R1/R2 = (N1/N2)2
-
R1/R2 = (N2/N1)2
Correct Answer
A. R1/R2 = N1/N2Explanation
The correct answer is R1/R2 = N1/N2. This relation is true because for no slip between the gears, the ratio of their radii should be equal to the ratio of their number of teeth. This ensures that the gears rotate at the same speed and there is no slipping between their teeth.Rate this question:
-
- 8.
Kinetic energy recovery system of EVs is also known as
-
Amplitude of voltage.
-
Amplitude of Current.
-
Frequency of AC.
-
None of these.
Correct Answer
A. Frequency of AC.Explanation
The given correct answer is "Frequency of AC." In the context of electric vehicles (EVs), the kinetic energy recovery system refers to the technology that converts the kinetic energy generated during braking or deceleration into electrical energy, which can then be stored and used to power the vehicle. This system is commonly associated with alternating current (AC) because the electrical energy generated and stored is typically in the form of AC. Therefore, the frequency of the AC refers to the number of complete cycles of alternating current per second, and it is an essential parameter in the operation of the kinetic energy recovery system in EVs.Rate this question:
-
- 9.
HEV (Hybrid Electric Vehicles or HEV) is
-
Fully electric with rechargeable batteries.
-
Powered by both petrol and electricity.
-
Battery recharged only by regenerative braking.
-
Charged with electricity from an external source.
Correct Answer(s)
A. Powered by both petrol and electricity.
A. Battery recharged only by regenerative braking.Explanation
HEV (Hybrid Electric Vehicles) are vehicles that are powered by both petrol and electricity. This means that they have an internal combustion engine that runs on petrol, as well as an electric motor that is powered by a rechargeable battery. The battery in an HEV can be recharged through regenerative braking, which converts the kinetic energy generated during braking into electrical energy to charge the battery. Therefore, the correct answer is that HEVs are powered by both petrol and electricity, and their batteries can be recharged through regenerative braking.Rate this question:
-
- 10.
In BLDC motor field winding is kept on
-
Stator
-
Rotor
-
Absent
-
Can be placed anywhere
Correct Answer
A. StatorExplanation
In a BLDC motor, the field winding is kept on the stator. The stator is the stationary part of the motor that houses the field winding. The field winding is responsible for creating a magnetic field that interacts with the rotor to generate rotational motion. Placing the field winding on the stator allows for a more efficient and reliable motor operation, as the stator remains stationary while the rotor rotates. This arrangement also simplifies the construction and maintenance of the motor.Rate this question:
-
- 11.
Typical BLDC doesn’t have
-
Commutator.
-
Permanent magnet.
-
Controller.
-
Fixed armature.
Correct Answer
A. Commutator.Explanation
A typical BLDC (Brushless DC) motor does not have a commutator. Commutators are found in brushed DC motors and are responsible for reversing the direction of current flow in the motor's armature windings. In a BLDC motor, the direction of current flow is controlled electronically by a controller, eliminating the need for a commutator. The other options, such as permanent magnet, controller, and fixed armature, are all components commonly found in a BLDC motor.Rate this question:
-
- 12.
In a universal joint as shown in the figure, the drive rotates at a constant angular velocity. Which of the following is correct
-
The angular velocity of driven shaft must be constant with time
-
The angular velocity of driven shaft may vary with time
-
The angular velocity of driven shaft must vary with time
-
Data is insufficient
Correct Answer
A. The angular velocity of driven shaft may vary with timeExplanation
In a universal joint, the drive rotates at a constant angular velocity. However, the driven shaft is connected to the drive shaft at an angle, which causes the driven shaft to experience varying angular velocities as it rotates. Therefore, the angular velocity of the driven shaft may vary with time.Rate this question:
-
- 13.
When a car takes a turn then the centripetal force is provided by the frictional force on the wheels acting towards the center of the turn. Which of the following is correct
-
The outer wheels in the turn offer lesser frictional force compared to inner wheels.
-
The inner wheels offer lesser frictional force than the outer wheels.
-
Both inner and outer wheels offer the same amount of frictional force.
-
Rear wheels offer more frictional force than the front one.
Correct Answer
A. The inner wheels offer lesser frictional force than the outer wheels.Explanation
When a car takes a turn, the centripetal force required to keep the car moving in a curved path is provided by the frictional force on the wheels. The frictional force acts towards the center of the turn. As the car turns, the outer wheels have a larger radius of curvature compared to the inner wheels. This means that the outer wheels need to exert a greater centripetal force to maintain the turn. Since the frictional force provides the centripetal force, the outer wheels experience a greater frictional force compared to the inner wheels. Therefore, the inner wheels offer lesser frictional force than the outer wheels.Rate this question:
-
- 14.
Which of the following metals can be best used as a cylinder block in an engine?
-
Steel
-
Aluminium
-
Low carbon Steel
-
Iron
Correct Answer
A. AluminiumExplanation
Aluminium is the best metal to be used as a cylinder block in an engine due to its lightweight and excellent heat transfer properties. It has a low density compared to other metals, allowing for reduced weight and improved fuel efficiency. Additionally, aluminium has high thermal conductivity, meaning it can quickly dissipate heat generated during engine operation, preventing overheating. Its corrosion resistance also makes it suitable for engine applications.Rate this question:
-
- 15.
The main function of the brake fluid is
-
Lubrication
-
Power transmission
-
Cooling
-
None of these
Correct Answer
A. Power transmissionExplanation
Brake fluid is responsible for transmitting the force applied on the brake pedal to the brake components, such as the brake calipers or wheel cylinders. It acts as a medium to transfer hydraulic pressure, allowing the brakes to engage and generate the necessary friction to slow down or stop the vehicle. Therefore, the main function of brake fluid is power transmission rather than lubrication or cooling.Rate this question:
-
- 16.
The self ignition temperature of diesel as compared to petrol is
-
Higher
-
Lower
-
Same
-
Depends on type of Engine
Correct Answer
A. LowerExplanation
The self-ignition temperature refers to the minimum temperature at which a substance can ignite spontaneously without an external ignition source. Diesel has a lower self-ignition temperature compared to petrol. This means that diesel is more prone to spontaneous combustion at lower temperatures than petrol.Rate this question:
-
- 17.
In a petrol engine, the high voltage for spark plug is in the order of
-
22 V
-
1000 V
-
5000 V
-
12000 V
Correct Answer
A. 12000 VExplanation
In a petrol engine, the high voltage for the spark plug is typically in the order of 12000 V. This high voltage is necessary to create a spark across the spark plug gap, which ignites the fuel-air mixture in the combustion chamber. The spark is generated by the ignition system, which includes components such as the ignition coil and distributor. The high voltage is required to overcome the resistance of the spark plug gap and create a strong enough spark to initiate combustion.Rate this question:
-
- 18.
The basic function of the suspension is to
-
Absorb vibration and impact forces from the road surface.
-
Ensure that the steering wheel can deliver a suitable amount of steering force.
-
Ensure that wheel alignment is not disturbed during driving.
-
Lower the center of mass of the chassis.
Correct Answer
A. Absorb vibration and impact forces from the road surface.Explanation
The suspension system in a vehicle is designed to absorb the vibrations and impact forces that occur when driving over uneven road surfaces. This helps to provide a smoother and more comfortable ride for the occupants of the vehicle. By absorbing these forces, the suspension system also helps to protect other components of the vehicle, such as the tires and chassis, from excessive wear and damage. Additionally, a well-functioning suspension system can improve the handling and stability of the vehicle, making it easier to control and maneuver.Rate this question:
-
- 19.
In petrol engines, during suction stroke, __________ is drawn in the cylinder
-
Only Air
-
Air and fuel
-
None of these
-
Only fuel
Correct Answer
A. Air and fuelExplanation
During the suction stroke in petrol engines, both air and fuel are drawn into the cylinder. This is because the suction stroke involves the downward movement of the piston, creating a vacuum in the cylinder. This vacuum allows the intake valve to open, allowing a mixture of air and fuel to enter the cylinder from the intake manifold. The air-fuel mixture is necessary for combustion to occur in the engine and produce power.Rate this question:
-
- 20.
In which of the following engine, Power/weight ratio is greatest
-
Spark ignition engine
-
Compression ignition engine
-
Induction motor
-
Hot steam engine
Correct Answer
A. Induction motorExplanation
The power/weight ratio is a measure of the power output of an engine relative to its weight. In the case of an induction motor, it has a high power/weight ratio because it is designed to be lightweight while still providing a high power output. This is achieved through the use of efficient electrical components and design techniques. On the other hand, spark ignition engines, compression ignition engines, and hot steam engines are typically heavier and have lower power/weight ratios due to the additional components and mechanisms required for their operation. Therefore, the induction motor has the greatest power/weight ratio among the given options.Rate this question:
-
- 21.
Which among the following has highest energy density
-
Diesel
-
Petrol
-
Battery
-
Hydrogen
Correct Answer
A. HydrogenExplanation
Hydrogen has the highest energy density among the given options. This is because hydrogen has a very high energy content per unit mass. It has the highest specific energy, meaning that a small amount of hydrogen can release a large amount of energy. Hydrogen also has a very low molecular weight, which contributes to its high energy density. Additionally, hydrogen can be easily compressed or liquefied, further increasing its energy density.Rate this question:
-
- 22.
Which of the following can be used for power transmission in intersecting shafts?
-
Spur gear
-
Helical gear
-
Bevel gear
-
Rack & pinion gear
Correct Answer
A. Bevel gearExplanation
Bevel gears can be used for power transmission in intersecting shafts because they have cone-shaped teeth that allow the gears to mesh at an angle. This design enables the transmission of power between shafts that are not parallel to each other. The angled teeth of bevel gears provide smooth and efficient power transfer, making them suitable for applications where intersecting shafts need to transmit power effectively.Rate this question:
-
- 23.
________is used to distribute the pressure of a nut evenly over the surface, so that the surface isn't damaged
Correct Answer
washerExplanation
A washer is used to distribute the pressure of a nut evenly over the surface, so that the surface isn't damaged. By placing a washer between the nut and the surface, the load is spread out over a larger area, reducing the chance of the surface getting damaged or deformed. This is especially important when dealing with softer materials or when tightening a nut with a high amount of force. The washer acts as a protective barrier, ensuring that the pressure is evenly distributed and preventing any potential damage to the surface.Rate this question:
- 24.
The ease with which petrol vapourizes is called its
-
Oxidation
-
Octane number
-
Volatility
-
Option 4
Correct Answer
A. VolatilityExplanation
Volatility refers to the ease with which a substance, in this case, petrol, vaporizes. Petrol has a relatively low boiling point, which means it can easily evaporate and turn into a vapor. This property is important for the combustion process in engines, as it allows petrol to mix with air and ignite efficiently. Therefore, the correct answer is volatility.Rate this question:
-
- 25.
During suction stroke, the inside pressure of the cylinder is
-
More than the atmospheric pressure.
-
Less than the atmospheric pressure.
-
Equal to the atmospheric pressure.
-
None of these
Correct Answer
A. Less than the atmospheric pressure.Explanation
During the suction stroke, the piston moves downwards, creating a larger volume inside the cylinder. This increase in volume leads to a decrease in pressure according to Boyle's law. As a result, the pressure inside the cylinder becomes lower than the atmospheric pressure, allowing the air or fuel mixture to be drawn into the cylinder. Therefore, the correct answer is "less than the atmospheric pressure."Rate this question:
-
Quiz Review Timeline (Updated): Mar 14, 2023 +
Our quizzes are rigorously reviewed, monitored and continuously updated by our expert board to maintain accuracy, relevance, and timeliness.
-
Current Version
-
Mar 14, 2023Quiz Edited by
ProProfs Editorial Team -
Oct 12, 2019Quiz Created by
Rohan Agarwal
Back to top