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TGSRTC TST/MST practice questions

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Question 1Road Transport Operations and Traffic Management

Under the Motor Vehicles Act, which document must a TGSRTC bus driver carry to prove authorization to drive a transport (passenger) vehicle?

  1. A valid driving licence endorsed for transport vehicles Correct answer.
  2. A conductor's badge
  3. A permit issued to the corporation
  4. A fitness certificate of the bus

Explanation

A driving licence with the appropriate transport vehicle endorsement authorizes the holder to drive a passenger transport vehicle. The fitness certificate and permit relate to the vehicle and the service, not to the driver's personal authorization. A conductor's badge is issued to conductors, not drivers.

Question 2Road Transport Operations and Traffic Management

A TGSRTC city service bus approaches a signalized intersection where the signal has turned amber as the bus is already within the junction. What is the correct action for the driver?

  1. Reverse out of the junction
  2. Stop immediately at the stop line
  3. Sound horn and accelerate through the red
  4. Clear the junction and proceed Correct answer.

Explanation

Once a vehicle has entered the junction, stopping abruptly is unsafe and obstructs cross traffic. The driver should complete the movement and clear the intersection. Stopping at the stop line applies only when the vehicle has not yet entered the junction.

Question 3Road Transport Operations and Traffic Management

What is the primary purpose of a bus bay (lay-by) at a TGSRTC bus stop?

  1. To provide space for ticket vending
  2. To serve as a parking area for idle buses
  3. To allow passengers to cross the road safely
  4. To let the bus stop clear of the running lane and avoid obstructing traffic Correct answer.

Explanation

A bus bay is an indented stopping area that allows the bus to pick up and set down passengers without blocking the through lane. This reduces rear-end conflicts and keeps traffic flowing. Passenger crossing and parking are separate provisions.

Question 4Road Transport Operations and Traffic Management

In a TGSRTC depot, a bus is scheduled to depart at 06:15. The crew reports at 06:05 and the vehicle is ready. Which operational term best describes the scheduled departure time shown on the duty roster?

  1. Turnaround time
  2. Schedule of operation (time-table) departure Correct answer.
  3. Running time
  4. Layover time

Explanation

The scheduled departure time is part of the time-table or schedule of operation that governs the service. Layover, running time, and turnaround time are components of the operating cycle but are not the departure time itself.

Question 5Road Transport Operations and Traffic Management

A TGSRTC bus is involved in a collision with a two-wheeler on a highway. Which is the first duty of the driver under traffic law?

  1. Render assistance to the injured and arrange medical aid Correct answer.
  2. Contact the insurer for claim settlement
  3. Report to the nearest police station before attending to the injured
  4. Move the bus away before any documentation

Explanation

The immediate legal and moral duty is to render assistance to injured persons and arrange medical help. Reporting to police and informing the insurer follow, but do not take precedence over saving life. Moving the vehicle before assistance can be considered negligence.

Question 6Road Transport Operations and Traffic Management

What does a solid continuous white line along the centre of a highway indicate to a TGSRTC driver?

  1. The lane is reserved for buses
  2. Overtaking is permitted with caution
  3. Parking is allowed on the left
  4. Crossing or changing lanes is prohibited Correct answer.

Explanation

A solid continuous centre line prohibits crossing or lane changing along its length. It is used where visibility or geometry makes overtaking unsafe. A broken line, by contrast, permits overtaking when safe.

Question 7Road Transport Operations and Traffic Management

A TGSRTC bus operating on a ghat (hill) section with a sharp blind curve should adopt which practice?

  1. Keep to the right to improve the turning radius
  2. Keep to the left, reduce speed, and sound the horn at the curve Correct answer.
  3. Switch off headlights to avoid glare
  4. Maintain speed to avoid stalling on the gradient

Explanation

On blind hill curves, the driver should stay left, slow down, and sound the horn to warn oncoming traffic. Keeping right on a blind curve risks head-on collision. Headlights should remain on for visibility.

Question 8Road Transport Operations and Traffic Management

Which of the following best defines 'headway' in the context of TGSRTC city bus operations?

  1. The time interval between two successive buses on the same route Correct answer.
  2. The total journey time of a bus
  3. The number of passengers carried per trip
  4. The distance between two consecutive bus stops

Explanation

Headway is the time gap between successive buses serving the same route or stop. It directly affects passenger waiting time and service frequency. Journey time and stop spacing are separate operational measures.

Question 9Road Transport Operations and Traffic Management

A driver observes a pedestrian stepping onto a zebra crossing at an uncontrolled intersection. What is the correct action for a TGSRTC bus driver?

  1. Sound the horn and continue at the same speed
  2. Change lanes to pass the pedestrian
  3. Slow down and give way to the pedestrian Correct answer.
  4. Proceed if the pedestrian is on the far half of the road

Explanation

Drivers must yield to pedestrians on a zebra crossing at uncontrolled intersections. The pedestrian has right of way once on the crossing, regardless of which half of the road they occupy. Horn use and lane changes do not override this duty.

Question 10Road Transport Operations and Traffic Management

In TGSRTC operations, what is the primary purpose of a 'route survey' before introducing a new bus service?

  1. To assess road conditions, demand, and operational feasibility Correct answer.
  2. To determine the number of conductors required
  3. To fix the fare stage structure only
  4. To estimate ticket revenue only

Explanation

A route survey examines road geometry, surface condition, demand, safety hazards, and operational feasibility before a service is introduced. Revenue estimation and fare stages are subsequent planning steps informed by the survey.

Question 11Road Transport Operations and Traffic Management

What is the correct action when a TGSRTC bus develops a brake failure while descending a hill?

  1. Accelerate to reach the bottom faster
  2. Switch off the engine and coast to a stop
  3. Apply the hand brake suddenly at full force
  4. Use engine braking by engaging a lower gear and apply the hand brake gradually Correct answer.

Explanation

With brake failure on a descent, the driver should use engine braking by shifting to a lower gear and apply the hand brake progressively. Coasting with the engine off removes engine braking and power steering assistance. Sudden full hand brake application can cause loss of control.

Question 12Road Transport Operations and Traffic Management

Which traffic sign shape is used for mandatory (regulatory) signs on Indian roads?

  1. Circular Correct answer.
  2. Triangular
  3. Octagonal
  4. Rectangular

Explanation

Mandatory or regulatory signs are circular with a red border, conveying prohibitions or restrictions. Triangular signs are cautionary and rectangular signs are informatory. Octagonal signs are used for stop.

Question 13Road Transport Operations and Traffic Management

A TGSRTC bus on an intercity route is running 45 minutes late due to a traffic blockade. What is the most appropriate operational response from the controller?

  1. Instruct the driver to exceed the speed limit to recover time
  2. Adjust the schedule, inform downstream stops, and manage crew duty hours Correct answer.
  3. Cancel the trip and refund all passengers
  4. Ignore the delay as it is within tolerance

Explanation

The controller should revise the schedule, communicate the delay to downstream stops, and ensure crew duty hours remain compliant. Speeding to recover time is unsafe and illegal. Cancellation is a last resort when operations cannot be sustained.

Question 14Road Transport Operations and Traffic Management

What is the principal function of a traffic island at a busy TGSRTC junction?

  1. To serve as a passenger waiting area
  2. To provide parking space for buses
  3. To separate conflicting traffic streams and guide turning movements Correct answer.
  4. To house traffic signal control cabinets

Explanation

Traffic islands channelize traffic, separate conflicting streams, and guide turning movements at junctions. They improve safety and capacity. Parking, control cabinets, and waiting areas are separate provisions.

Question 15Road Transport Operations and Traffic Management

A TGSRTC driver is scheduled for a long-distance night trip. Which practice best manages driver fatigue?

  1. Keeping the cabin warm and dark
  2. Driving faster to finish the trip early
  3. Drinking strong coffee throughout the trip
  4. Scheduling rest breaks and rotating drivers as per duty norms Correct answer.

Explanation

Fatigue is best managed through planned rest breaks and crew rotation in line with duty-hour regulations. Stimulants provide only temporary relief and cannot substitute for rest. Speeding and warm, dark cabins increase fatigue risk.

Question 16Road Transport Operations and Traffic Management

In the context of TGSRTC bus operations, what does 'dead mileage' refer to?

  1. Distance covered on the return trip
  2. Distance covered on a full passenger load
  3. Mileage lost due to tyre wear
  4. Distance run without carrying passengers, such as from depot to starting point Correct answer.

Explanation

Dead mileage is the distance a bus travels without carrying passengers, such as from the depot to the route starting point or between trips. It is a cost without revenue and is minimized in scheduling. Loaded mileage and return trips are not dead mileage.

Question 17Road Transport Operations and Traffic Management

A TGSRTC bus must turn right at a signalized intersection with a dedicated right-turn arrow that is currently red while the straight-ahead green is on. What should the driver do?

  1. Sound the horn and proceed
  2. Turn right as the straight green implies permission
  3. Wait for the right-turn arrow to turn green Correct answer.
  4. Turn right after yielding to oncoming traffic

Explanation

A dedicated right-turn arrow controls that movement independently. When it is red, the driver must wait even if the straight-ahead signal is green. The straight green applies only to straight-through traffic.

Question 18Road Transport Operations and Traffic Management

Which of the following is a key responsibility of a TGSRTC conductor during the journey?

  1. Driving the bus when the driver is on break
  2. Carrying out vehicle maintenance checks
  3. Issuing tickets, collecting fares, and ensuring passenger safety Correct answer.
  4. Planning the route schedule

Explanation

The conductor issues tickets, collects fares, and is responsible for passenger safety and orderly boarding and alighting. Driving and maintenance are not the conductor's duties. Route scheduling is done by the depot planning section.

Question 19Road Transport Operations and Traffic Management

What is the purpose of a 'fare stage' in TGSRTC bus operations?

  1. To indicate the location of the depot
  2. To mark the point where the driver changes
  3. To mark the bus maintenance point
  4. To define the point up to which a particular fare is charged Correct answer.

Explanation

A fare stage is a point on the route up to which a specified fare applies. Passengers are charged based on the number of fare stages travelled. It is not related to crew change or depot location.

Question 20Road Transport Operations and Traffic Management

A TGSRTC bus is approaching a level crossing with the gate open but the signal light flashing. What is the correct action?

  1. Sound the horn and cross slowly
  2. Stop before the crossing and wait until it is safe Correct answer.
  3. Speed up to cross before the gate closes
  4. Proceed as the gate is open

Explanation

A flashing signal at a level crossing indicates an approaching train, regardless of gate position. The driver must stop and wait until the crossing is clear and safe. Proceeding on an open gate alone is unsafe.

Question 21Road Transport Operations and Traffic Management

Which measure best reduces overcrowding and improves reliability on a high-demand TGSRTC city route?

  1. Increasing the fare during peak hours
  2. Deploying additional buses and reducing headway during peak periods Correct answer.
  3. Extending the route length
  4. Reducing the number of stops on the route

Explanation

Adding buses and reducing headway during peak periods increases capacity and improves reliability. Fare increases do not reduce demand effectively and can shift passengers away. Reducing stops or extending routes does not address capacity.

Question 22Road Transport Operations and Traffic Management

What does the term 'turnaround time' mean in TGSRTC depot operations?

  1. The time taken to issue tickets
  2. The time taken by a bus to complete a return trip from terminus to terminus Correct answer.
  3. The time taken to refuel a bus
  4. The time taken to change a tyre

Explanation

Turnaround time is the total time a bus takes to travel from a terminus to the other end and return, including layover. It is used to compute vehicle requirement and schedule feasibility. Refuelling and ticket issuance are separate activities.

Question 23Road Transport Operations and Traffic Management

Which of the following is the correct interpretation of a 'Give Way' sign for a TGSRTC driver?

  1. Sound the horn and proceed without yielding
  2. Accelerate to merge ahead of other vehicles
  3. Proceed only after yielding to traffic on the priority road Correct answer.
  4. Stop completely before proceeding

Explanation

A Give Way sign requires the driver to yield to traffic on the priority road and proceed only when it is safe. A complete stop is required at a Stop sign, not at Give Way. Accelerating or using the horn does not override the duty to yield.

Question 24Road Transport Operations and Traffic Management

A TGSRTC bus encounters a flooded section of road during monsoon. What is the safest operational decision?

  1. Drive through slowly in a low gear regardless of depth
  2. Stop and assess the depth; do not proceed if depth is unsafe Correct answer.
  3. Drive through at high speed to avoid stalling
  4. Reverse along the road to find an alternate route

Explanation

The driver should stop and assess water depth before proceeding. If depth is unsafe, the bus should not enter, and an alternate route or diversion should be arranged. High speed or blind entry risks engine damage and loss of control.

Question 25Road Transport Operations and Traffic Management

In TGSRTC operations, what is the main objective of 'crew scheduling'?

  1. To assign drivers and conductors to duties while respecting duty-hour rules and rest Correct answer.
  2. To minimize the number of buses in the depot
  3. To fix the fare structure
  4. To maximize the number of trips per day

Explanation

Crew scheduling assigns drivers and conductors to duties while complying with duty-hour limits and mandatory rest. It balances operational needs with legal and safety requirements. Fare fixation and bus count are separate planning functions.

Question 26Road Transport Operations and Traffic Management

A TGSRTC city bus is timed to leave a terminal every 8 minutes, but during peak hour the depot dispatches two buses together and then leaves a 16-minute gap. Which term describes this operational problem?

  1. Bunching of services Correct answer.
  2. Turnaround time
  3. Dead mileage
  4. Fare stage spacing

Explanation

Bunching occurs when scheduled headway breaks down and vehicles arrive or depart in clusters, followed by an abnormally long gap. It wastes capacity on the bunched run and leaves waiting passengers stranded during the gap. Dispatchers regulate departures at terminals to preserve even headway.

Question 27Road Transport Operations and Traffic Management

A TGSRTC bus is stopped at a bus bay on a two-lane highway. Which action best protects passengers boarding and alighting?

  1. Stopping a few metres past the bay to shorten the walk for passengers
  2. Stopping with hazard lights on in the middle of the traffic lane
  3. Stopping fully inside the bay so the rear does not protrude into the carriageway Correct answer.
  4. Stopping on the shoulder facing against the direction of traffic

Explanation

A bus bay exists so that a stopped bus does not obstruct through traffic and passengers can board away from moving vehicles. The whole bus, including the rear overhang, must be within the bay. Partial occupation forces following traffic to swerve around a stationary bus, which is a common cause of rear-end and side-swipe collisions.

Question 28Road Transport Operations and Traffic Management

What is the primary purpose of a 'traffic census' conducted on a state highway corridor by a transport authority?

  1. To record the fuel consumption of each government bus on the corridor
  2. To fix the fare payable by passengers between two stops
  3. To list the names of crew members rostered on the corridor
  4. To count and classify vehicles and passengers so road capacity and service demand can be assessed Correct answer.

Explanation

A traffic census records volumes, vehicle classes and often occupancy over defined periods at fixed points. The resulting data support capacity assessment, road improvement planning and decisions on augmenting bus services. It is an input to planning, not a record of individual vehicle or crew performance.

Question 29Road Transport Operations and Traffic Management

Which document authorises a TGSRTC bus to be run on a particular route and specifies the route, timings and conditions of operation?

  1. The trip sheet issued to the crew Correct answer.
  2. The depot's staff attendance register
  3. The vehicle fitness certificate
  4. The conductor's cash book

Explanation

The trip sheet is issued for each trip and carries the route, scheduled timings, vehicle number and crew particulars, so it links the vehicle to an authorised service. It also serves as the operational record against which punctuality and duty performance are checked. Other certificates and registers support operations but do not authorise a specific trip.

Question 30Road Transport Operations and Traffic Management

A TGSRTC bus is approaching a signalised junction where the signal has failed and no traffic warden is present. What is the safest procedure?

  1. Stop permanently and wait until a warden arrives
  2. Follow the vehicle ahead closely through the junction
  3. Accelerate to clear the junction before cross traffic arrives
  4. Slow down, treat the junction as uncontrolled and proceed only after yielding to traffic already in it Correct answer.

Explanation

When signals fail, the junction reverts to an uncontrolled state in which priority is decided by the normal rules of the road. The driver must reduce speed, observe all approaches and enter only when it is clear and safe. This prevents the high-speed right-angle collisions typical of failed-signal junctions.

Question 31Road Transport Operations and Traffic Management

During monsoon, a culvert on a rural TGSRTC route is submerged and the depth is uncertain. Which decision is operationally correct?

  1. Stop short of the water, inform the controller and suspend the trip rather than attempt the crossing Correct answer.
  2. Follow a tractor across since heavier vehicles make the route safe
  3. Cross at speed so the momentum carries the bus through
  4. Probe with a stick and cross if the water appears below the wheel hub

Explanation

Flowing water over a submerged culvert can hide scoured road surface and can float or sweep away even a laden bus. The crew must halt before the water, report to the depot controller and hold or divert the service. Attempting the crossing risks passenger lives and loss of the vehicle.

Question 32Road Transport Operations and Traffic Management

A driver on a long-distance TGSRTC service feels drowsy about two hours after departure. Which action is most consistent with fatigue management rules?

  1. Take a stimulant and continue without informing anyone
  2. Open the window and continue at a higher speed to finish sooner
  3. Stop at the next safe place and rest before continuing the trip Correct answer.
  4. Ask the conductor to keep talking and press on to the destination

Explanation

Drowsiness indicates the driver's alertness is already impaired, and no in-cab trick restores it reliably. The safe response is to stop at a safe location and rest, and to report the condition so the schedule can be adjusted. Continuing while drowsy is a recognised cause of run-off-road and head-on crashes.

Question 33Road Transport Operations and Traffic Management

What is the main purpose of a 'route rationalisation' exercise in a city bus network?

  1. To replace buses with smaller vehicles on all routes
  2. To realign routes and frequencies so that capacity matches observed passenger demand Correct answer.
  3. To reduce the wages paid to the crew on each route
  4. To shorten the distance between consecutive fare stages

Explanation

Route rationalisation reviews overlapping routes, load profiles and demand so that services are redeployed where they are needed. The aim is better utilisation of buses and crews and shorter waiting times for passengers. It is a planning exercise, not a cost-cutting measure aimed at wages.

Question 34Road Transport Operations and Traffic Management

Two TGSRTC buses arrive at a single-berth bus stop at the same time. What is the correct practice for the second driver?

  1. Pull alongside the first bus so both can load passengers together
  2. Wait behind the first bus and move into the berth only after it has departed Correct answer.
  3. Overtake and stop ahead of the first bus in the carriageway
  4. Sound the horn continuously until the first bus moves

Explanation

A single berth can hold one bus safely, so the second bus must queue behind and take the berth after the first leaves. This keeps boarding passengers away from moving traffic and avoids double-parking in the lane. Loading alongside another bus exposes passengers to passing vehicles.

Question 35Road Transport Operations and Traffic Management

A TGSRTC bus is descending a long ghat section. Which gear and braking practice should the driver follow?

  1. Keep in neutral and rely on the foot brake continuously
  2. Use the top gear and brake hard only at the hairpin bends
  3. Select a low gear and use engine braking, applying the service brake intermittently Correct answer.
  4. Switch off the engine to save fuel and coast downhill

Explanation

A low gear lets engine compression hold the vehicle back so the service brake is used only briefly and does not overheat. Continuous braking on a long descent causes fade and can lead to total brake loss. Coasting in neutral or with the engine off removes engine braking and is dangerous.

Question 36Road Transport Operations and Traffic Management

A TGSRTC bus is involved in a minor collision with a two-wheeler in which a rider sustains injuries. What should the crew do first?

  1. Stop, render first aid and arrange to shift the injured person to hospital, then report to police and depot Correct answer.
  2. Settle the matter with cash on the spot and proceed
  3. Move the bus away quickly to avoid traffic congestion
  4. Continue the trip and report the matter at the depot after completing the schedule

Explanation

In any accident involving injury, the crew's first duty is to stop, help the injured and arrange medical attention. The accident must then be reported to the police and to the depot so that statutory and insurance formalities can follow. Leaving the scene or privately settling an injury case is unlawful.

Question 37Road Transport Operations and Traffic Management

A TGSRTC bus is held up because a goods lorry has broken down in the middle of a narrow bridge. What is the most appropriate action by the driver?

  1. Stop at a safe distance, switch on hazard lights and wait for the obstruction to be cleared Correct answer.
  2. Drive onto the footpath to bypass the blockage
  3. Squeeze past the lorry on the bridge edge to keep the schedule
  4. Reverse off the bridge at speed without assistance

Explanation

A narrow bridge gives no safe overtaking space, so the bus must halt at a safe distance with hazard lamps on and wait for the obstruction to clear. The crew should inform the controller about the delay. Attempting to squeeze past risks a collision or a fall from the bridge.

Question 38Road Transport Operations and Traffic Management

A TGSRTC bus is scheduled on a route where a procession is expected to block the main road for several hours. Which planning response is most appropriate before departure?

  1. Notify the controller and arrange a diversion or short-working of the service in advance Correct answer.
  2. Ask the conductor to guide the bus through the crowd on foot
  3. Run the bus on the normal route and decide only when the blockade is met
  4. Cancel the service without informing passengers

Explanation

Advance information about a known blockade allows the controller to plan a diversion or short-working, and to inform passengers before they board. Reacting only at the blockade leaves passengers stranded and the bus trapped. Crowd management is not a conductor's task.

Question 39Road Transport Operations and Traffic Management

A TGSRTC depot finds that a particular city route has high peak load but very low off-peak load. Which scheduling measure best matches capacity to demand?

  1. Operate the same frequency throughout the day to simplify rostering
  2. Increase the fare only during the off-peak period
  3. Operate more trips in the peak and fewer in the off-peak while keeping the same fleet Correct answer.
  4. Withdraw the route because average occupancy is low

Explanation

When demand is sharply peaked, the efficient response is to vary frequency so that more buses run when loads are high and fewer when they are low. This improves load factor and reduces wasted bus-hours without withdrawing service. Uniform frequency over-supplies the off-peak and under-supplies the peak.

Question 40Road Transport Operations and Traffic Management

A TGSRTC bus is timed to reach a mid-route control point at 10:15 but arrives at 10:29. What is the operational significance of this record?

  1. It proves that the driver exceeded the speed limit on the route
  2. It fixes the fare payable by passengers who boarded after that point
  3. It shows that the vehicle's fitness certificate has lapsed
  4. It measures schedule adherence at a control point and triggers corrective regulation of the trip Correct answer.

Explanation

Control-point timings are the standard means of checking whether a trip is running to schedule. A recorded delay of fourteen minutes signals that the service is late and allows the controller to regulate the next departure or adjust the turn. It is a punctuality measure, not evidence of speeding or of document validity.

Question 41Motor Vehicle Mechanics and Automotive Engineering

In a diesel engine, the component that pressurises and delivers fuel to the injectors on a common rail system is the:

  1. Lift pump
  2. Feed pump
  3. Hand primer pump
  4. High-pressure fuel pump Correct answer.

Explanation

The high-pressure pump raises diesel to rail pressure (often over 1000 bar) before the ECU-controlled injectors meter it. The feed or lift pump only supplies low-pressure fuel from the tank to the high-pressure stage.

Question 42Motor Vehicle Mechanics and Automotive Engineering

The main function of a turbocharger in a TGSRTC bus diesel engine is to:

  1. Increase the mass of air entering the cylinder Correct answer.
  2. Filter dust from intake air
  3. Reduce exhaust noise
  4. Cool the engine coolant

Explanation

An exhaust-driven turbine spins a compressor that forces denser air into the cylinders, allowing more fuel to be burnt and more power from the same displacement. Cooling, silencing and filtration are handled by other systems.

Question 43Motor Vehicle Mechanics and Automotive Engineering

The clutch in a manual-transmission bus is provided mainly to:

  1. Lubricate the gearbox
  2. Disconnect engine power from the gearbox during gear changes Correct answer.
  3. Increase engine torque at low speed
  4. Reduce engine vibration

Explanation

The clutch momentarily separates the engine from the transmission so gears can be selected smoothly and the vehicle can start from rest. Torque multiplication and lubrication are functions of the gearbox and its oil.

Question 44Motor Vehicle Mechanics and Automotive Engineering

Which component converts the rotary motion of the steering wheel into linear movement of the steering linkage?

  1. Wheel hub
  2. King pin
  3. Tie rod end
  4. Steering gear box Correct answer.

Explanation

The steering gear box (recirculating ball or rack type) reduces effort and converts rotation into linear motion of the linkage. King pins and tie rod ends are joints in the linkage, and the hub carries the wheel bearing.

Question 45Motor Vehicle Mechanics and Automotive Engineering

The specific gravity of a fully charged lead-acid battery electrolyte at 25 degrees Celsius is approximately:

  1. 1.100 to 1.120
  2. 1.260 to 1.280 Correct answer.
  3. 0.850 to 0.900
  4. 1.400 to 1.450

Explanation

A healthy fully charged lead-acid cell reads about 1.260 to 1.280 specific gravity at 25 degrees Celsius. A reading near 1.100 to 1.120 indicates a heavily discharged battery.

Question 46Motor Vehicle Mechanics and Automotive Engineering

In a four-stroke diesel engine, the sequence of strokes in correct order is:

  1. Compression, suction, power, exhaust
  2. Suction, power, compression, exhaust
  3. Power, suction, compression, exhaust
  4. Suction, compression, power, exhaust Correct answer.

Explanation

The four-stroke cycle proceeds as intake (suction), compression, power (expansion) and exhaust, driven by two crankshaft revolutions. Any other order does not match the valve and piston timing.

Question 47Motor Vehicle Mechanics and Automotive Engineering

The purpose of a differential in a rear-axle-driven bus is to:

  1. Engage and disengage the propeller shaft
  2. Allow the rear wheels to turn at different speeds while cornering Correct answer.
  3. Absorb road shocks
  4. Increase the final drive ratio

Explanation

During a turn, the outer wheel travels a longer path than the inner wheel; the differential permits different wheel speeds while still transmitting torque. Road shocks are absorbed by suspension, and ratio change is a separate function of the crown and pinion.

Question 48Motor Vehicle Mechanics and Automotive Engineering

Brake fade during prolonged downhill braking of a heavy bus is most commonly caused by:

  1. Low tyre pressure
  2. Overheating of the brake friction surfaces Correct answer.
  3. Air entering the hydraulic circuit
  4. Worn wheel bearings

Explanation

Continuous braking raises drum or disc temperature, reducing the friction coefficient of the lining material, which is called fade. Air in the circuit or mechanical wear produce different symptoms, not heat-related loss of retardation.

Question 49Motor Vehicle Mechanics and Automotive Engineering

A bus diesel engine overheats only when the vehicle is climbing with a full load, while cooling is normal on level roads. Which cause is most likely?

  1. A faulty thermostat stuck open
  2. A blown head gasket
  3. A partially restricted radiator core or a slipping fan drive Correct answer.
  4. A weak battery

Explanation

Higher engine load demands more heat rejection; if the radiator is scaled or the fan drive slips, cooling capacity is insufficient only under load. A stuck-open thermostat usually causes overcooling, and a weak battery does not affect cooling.

Question 50Motor Vehicle Mechanics and Automotive Engineering

During a road test, a bus pulls to the left when the brakes are applied. The most probable cause is:

  1. Equal wear on both front tyres
  2. A worn steering wheel
  3. A seized or contaminated brake on the right side Correct answer.
  4. A low coolant level

Explanation

If the right brake is not developing full friction, the left brake dominates and the vehicle pulls left. Equal tyre wear and coolant level do not produce a braking pull, and the steering wheel itself does not cause it.