I85PREP
⌘ K
SST study materials
SST study resources

SST (Pakistan Educators Recruitment Tests) practice questions

One question at a time. Build your SST understanding.

First 50 of 200 questions. Each one lists the choices, the correct answer, and an explanation. The checker at the top of this page saves progress in this browser when it is available.

Continue in the practice tool above to load more questions, 50 at a time.

Question 1Fundamentals, Terminology, and Core Concepts

Which term describes a condition that has the potential to cause harm to people, property, or the environment?

  1. Risk
  2. Mishap
  3. Hazard Correct answer.
  4. Exposure

Explanation

A hazard is a condition with the potential to cause harm; it exists whether or not anyone is actually harmed. Risk combines the severity of that potential harm with the likelihood of occurrence, and a mishap is an event in which harm has already occurred.

Question 2Fundamentals, Terminology, and Core Concepts

In system safety practice, risk is best defined as which of the following?

  1. The cost of the controls needed to reduce an identified hazard
  2. The total number of hazards identified during the analysis
  3. Any condition that could lead to injury or equipment damage
  4. The combination of the severity of harm and its likelihood Correct answer.

Explanation

Risk is a combination of the severity of a potential harm and the likelihood that the harm occurs. Neither factor alone defines risk, and the number of hazards found or the cost of controls is not part of the definition.

Question 3Fundamentals, Terminology, and Core Concepts

A mishap is best described as which of the following?

  1. An unplanned event that results in harm or damage Correct answer.
  2. A planned test of a safety-critical function
  3. A hazard that has been eliminated by design
  4. A documented assumption about the behavior of the system

Explanation

A mishap is an unplanned event, or series of events, that results in harm, injury, or damage. A hazard only has the potential to cause such an outcome, while a mishap is the realization of that potential.

Question 4Fundamentals, Terminology, and Core Concepts

In risk assessment, severity refers to which of the following?

  1. How often a hazard is expected to occur
  2. How quickly a hazard can be detected
  3. The degree of harm that could result from a hazard Correct answer.
  4. The number of people exposed to a hazard at one time

Explanation

Severity expresses the degree of harm, injury, or damage that could result from a hazard. Frequency belongs to probability, while exposure and detectability are separate considerations.

Question 5Fundamentals, Terminology, and Core Concepts

Which term expresses how often or how likely a hazardous outcome is to occur?

  1. Probability Correct answer.
  2. Severity
  3. Criticality
  4. Detectability

Explanation

Probability, or likelihood, expresses how often or how likely a hazardous outcome is within a stated period or set of conditions. Severity addresses the consequence, detectability addresses how readily a failure is discovered, and criticality is a combined ranking.

Question 6Fundamentals, Terminology, and Core Concepts

Residual risk is best described as the risk that does which of the following?

  1. Exists before any controls are applied
  2. Is created only by software failures
  3. Remains after safety controls have been implemented Correct answer.
  4. Must always be accepted by the end user

Explanation

Residual risk is what remains after safety controls have been applied, and it is compared against the acceptance criteria for the program. The risk estimated before controls are applied is called the initial risk.

Question 7Fundamentals, Terminology, and Core Concepts

Which of the following is the most effective category of hazard control in the standard order of precedence?

  1. Design changes that eliminate or reduce the hazard Correct answer.
  2. Warning labels and training
  3. Personal protective equipment
  4. Procedures and administrative controls

Explanation

In the standard precedence order, design changes that eliminate or reduce the hazard are preferred because they do not depend on human behavior. Warnings, procedures, and protective equipment come later and are generally less reliable.

Question 8Fundamentals, Terminology, and Core Concepts

A safety-critical function is one that does which of the following?

  1. Is performed only during scheduled maintenance and inspection activities
  2. Is documented in the user manual
  3. Adds cost without adding any operational capability
  4. Its failure or incorrect execution could lead to a mishap Correct answer.

Explanation

A safety-critical function is one whose failure or incorrect performance could directly contribute to a mishap. Because of that consequence, such functions receive additional analysis, verification, and control.

Question 9Fundamentals, Terminology, and Core Concepts

A risk matrix is used primarily to do which of the following?

  1. Determine the cost of the safety program
  2. Combine severity and likelihood so hazards can be ranked Correct answer.
  3. Calculate the exact failure rate of each individual component
  4. Replace the need for hazard identification

Explanation

A risk matrix pairs severity categories with likelihood categories so that hazards receive a comparable risk level. That ranking supports prioritization and decisions about which hazards need further controls.

Question 10Fundamentals, Terminology, and Core Concepts

The principle of ALARP requires that risk be reduced in which of the following ways?

  1. To a level that is as low as reasonably practicable Correct answer.
  2. Only until the safety budget is exhausted
  3. Only for hazards rated as catastrophic
  4. To zero in every case

Explanation

ALARP means risk is reduced until further reduction would be grossly disproportionate to the benefit gained. It does not require zero risk, and the justification is based on reasonable practicability rather than budget alone.

Question 11Fundamentals, Terminology, and Core Concepts

Failure Mode and Effects Analysis (FMEA) primarily examines which of the following?

  1. Operator error rates observed across a full work shift
  2. The chronological sequence of events that follows an accident
  3. The cost of spare parts inventory
  4. How a component can fail and what effect the failure has Correct answer.

Explanation

FMEA is an inductive, bottom-up technique that examines how each component or function can fail and what effect that failure has on the system. Its results are used to prioritize failures by severity and likelihood.

Question 12Fundamentals, Terminology, and Core Concepts

Fault tree analysis is a technique that does which of the following?

  1. Measures noise and other physical stressors in a workplace
  2. Starts from a top event and works down to basic causes Correct answer.
  3. Lists every component in the system bill of materials
  4. Predicts the staffing levels required for scheduled maintenance

Explanation

Fault tree analysis is deductive: it begins with a defined undesired top event and works down through the combinations of basic events that could produce it. It is often used to quantify the probability of the top event.

Question 13Fundamentals, Terminology, and Core Concepts

A close call, or near miss, is an event that does which of the following?

  1. Could have caused harm but did not result in a mishap Correct answer.
  2. Is not relevant to hazard identification
  3. Is reported only to the insurance carrier
  4. Always involves an injury to a worker

Explanation

A close call has the potential for harm but does not produce injury or damage. Because it reveals a hazard without the cost of a mishap, close-call reporting is a valuable source of safety information.

Question 14Fundamentals, Terminology, and Core Concepts

A preliminary hazard list (PHL) is typically produced at which point?

  1. Only for systems that contain safety-critical software
  2. At the very end of a system's service life
  3. Only after a mishap has occurred
  4. Early in a program, before detailed analyses are performed Correct answer.

Explanation

The preliminary hazard list is an early, coarse look at hazards, produced during concept or requirements work to guide later analyses. It is intentionally generated before detailed design data are available.

Question 15Fundamentals, Terminology, and Core Concepts

The main purpose of a hazard tracking system is to do which of the following?

  1. Replace system safety analyses
  2. Store design drawings and their full revision history
  3. Track each hazard's status, controls, and closure evidence Correct answer.
  4. Record employee training hours

Explanation

A hazard tracking system records each identified hazard with its risk, assigned controls, owner, and closure evidence so that nothing is lost across the program. It also supports verification that controls were implemented and were effective.

Question 16Fundamentals, Terminology, and Core Concepts

In the standard order of precedence for hazard control, which step follows 'design for minimum risk'?

  1. Warning devices and training
  2. Acceptance with no further controls
  3. Incorporating safety devices or controls into the design Correct answer.
  4. Hazard elimination

Explanation

The accepted precedence is design for minimum risk, then incorporate safety devices, then provide warning devices, and finally develop procedures and training. Safety devices come after design changes because they add protective hardware rather than removing the hazard.

Question 17Fundamentals, Terminology, and Core Concepts

Human factors analysis in system safety focuses on which of the following?

  1. The physical dimensions and weight of shipping containers
  2. The number of employees assigned to each production unit
  3. How people interact with equipment and where error is likely Correct answer.
  4. The accounting cost of labor across production shifts

Explanation

Human factors examines the interaction among people, equipment, and procedures, and how design choices make error more or less likely. Its findings feed into design changes, procedures, and training.

Question 18Fundamentals, Terminology, and Core Concepts

During a safety assessment, a team finds that a software routine can issue a command at the wrong moment. Which statement best explains why this must be treated as a hazard contributor?

  1. Software failures are systematic and traceable to requirements and logic Correct answer.
  2. Software failures always produce identical and easily predicted outcomes
  3. Software reliability always exceeds hardware reliability
  4. Software can be tested exhaustively before fielding

Explanation

Software failures are systematic: they arise from requirement, design, or logic flaws and recur under the same conditions. Because random-failure reliability models do not apply, software's contribution to hazards is traced through requirements and logic.

Question 19Fundamentals, Terminology, and Core Concepts

System safety is most effective when it is applied in which of the following ways?

  1. Throughout the life cycle, starting in concept and design Correct answer.
  2. Only during production and manufacturing
  3. Only after fielding, once operational failures begin to appear
  4. Only during disposal and decommissioning

Explanation

Safety has the greatest influence early, when requirements and design can still be changed, and it must continue through production, operation, and disposal. Applying it only in a single phase leaves few options other than procedural controls.

Question 20Fundamentals, Terminology, and Core Concepts

Acceptance of a residual risk is properly performed by which of the following?

  1. The authority designated to accept that level of risk Correct answer.
  2. Any member of the test team who witnessed the hazard
  3. The equipment vendor or its authorized supplier
  4. The analyst who performed the original risk assessment

Explanation

Risk acceptance is a management decision made by the authority designated for that level of risk, based on the documented analysis. Analysts, testers, and vendors supply information but do not own the acceptance decision.

Question 21Fundamentals, Terminology, and Core Concepts

A design is described as inherently safe when the hazard has been handled in which of the following ways?

  1. Covered by a prominent warning label on the equipment
  2. Controlled mainly by operator training and procedures
  3. Eliminated or reduced by the design itself Correct answer.
  4. Deferred to a later phase of the acquisition program

Explanation

Inherent safety means the hazard has been removed or reduced by the design itself, so safety does not depend on added devices, warnings, or human behavior. Warning labels and training are add-on controls and are not inherent design features.

Question 22Fundamentals, Terminology, and Core Concepts

In STPA-style analysis, an unsafe control action is one that does which of the following?

  1. Occurs only in hardware components rather than in software
  2. In a given context leads to a hazard, by action or inaction Correct answer.
  3. Appears on the operator's checklist as a required step
  4. Has already been validated by the test team

Explanation

An unsafe control action is a control action that, in a particular context, leads to a hazard. It includes providing a command when it should not be provided, failing to provide it, or providing it at the wrong time or for the wrong duration.

Question 23Fundamentals, Terminology, and Core Concepts

A common-cause failure is significant in system safety for which of the following reasons?

  1. It is always detected by built-in test
  2. One event can defeat several independent controls at once Correct answer.
  3. It can occur only in systems that are not safety-critical
  4. It always involves human error rather than hardware

Explanation

Common-cause failure matters because redundancy only helps when failures are truly independent. A shared source such as power, software, environment, or maintenance error can disable several channels or controls simultaneously.

Question 24Fundamentals, Terminology, and Core Concepts

A Safety Assessment Report is best described as a document that does which of the following?

  1. Records the purchase orders for safety equipment
  2. Certifies that no hazards remain in the system
  3. Replaces all hazard analyses with a single test report
  4. Summarizes hazards, controls, and residual risk Correct answer.

Explanation

The Safety Assessment Report consolidates the hazard analyses, implemented controls, and residual risk so decision makers can judge whether the system is safe to proceed. It is a summary and decision aid, not a substitute for the underlying analyses.

Question 25Fundamentals, Terminology, and Core Concepts

In a risk assessment, why are severity and probability evaluated separately?

  1. Because only severity matters for catastrophic hazards
  2. Because probability cannot be estimated until testing is complete
  3. Because severity is always measured in dollars
  4. Severity is the consequence; probability is how likely it is Correct answer.

Explanation

Severity captures the consequence of the harm, while probability captures how likely that consequence is. Keeping them separate shows whether risk is driven by a severe but rare outcome or a frequent but minor one, and the two are then combined into an overall risk level.

Question 26Fundamentals, Terminology, and Core Concepts

A System Safety Program Plan (SSPP) primarily serves which purpose?

  1. It lists every hazard identified by the program.
  2. It certifies acceptance of final residual risk.
  3. It defines how safety work is organized and performed. Correct answer.
  4. It records every mishap that occurs during developmental testing.

Explanation

The SSPP is the program's planning document for system safety. It establishes responsibilities, resources, milestones, and the methods to be used, rather than serving as a hazard log or a record of mishaps.

Question 27Fundamentals, Terminology, and Core Concepts

Which statement best distinguishes a hazard from a risk?

  1. A hazard is an event that has already caused harm, while a risk is an event that might do so.
  2. A hazard applies only to hardware, while a risk applies only to software.
  3. A hazard is a condition that could cause harm; a risk combines likelihood and severity. Correct answer.
  4. A hazard is the probability of harm, while a risk is the consequence of harm.

Explanation

A hazard is a potential source or condition that can cause harm. Risk expresses the combination of how likely that harm is and how severe it would be, so the two terms are not interchangeable.

Question 28Fundamentals, Terminology, and Core Concepts

A fail-safe design approach is best illustrated by which of the following?

  1. Adding a warning label that alerts operators to a dangerous voltage.
  2. Increasing the strength of a pressure vessel so it never leaks.
  3. Requiring inspectors to check a critical dimension after assembly.
  4. Designing a valve to return to a safe position if power is lost. Correct answer.

Explanation

Fail-safe design ensures that a failure or loss of power or energy drives the system to a predetermined safe state. Administrative controls and inspection do not provide this inherent failure response.

Question 29Fundamentals, Terminology, and Core Concepts

Which of the following best describes a safety requirement?

  1. A list of hazards that remain after all controls are applied.
  2. A general goal to improve safety culture across the program.
  3. A design feature that has already been proven safe in prior service.
  4. A verifiable statement that a system must meet to control a hazard. Correct answer.

Explanation

Safety requirements are derived from hazard analyses and state what the system must do or be to eliminate or control a hazard. They must be verifiable so compliance can be demonstrated.

Question 30Fundamentals, Terminology, and Core Concepts

In a safety-critical system, a single-point failure is best characterized as one that does which of the following?

  1. is caused by a common design defect affecting redundant channels.
  2. removes a required safety function with no independent backup. Correct answer.
  3. occurs only when two or more independent causes act together.
  4. has no effect on safety because it is detected by inspection.

Explanation

A single-point failure is one failure that directly removes a safety function and has no independent backup or redundancy. It is distinct from common-cause failure, where a shared cause defeats multiple channels.

Question 31Installation, Setup, and Configuration

Which source should you check first to confirm the electrical and environmental requirements of a new appliance before it is installed?

  1. An online community forum post from another site
  2. Notes left by the contractor who wired the room
  3. The vendor's marketing brochure for the product line
  4. The manufacturer's specifications sheet Correct answer.

Explanation

Published manufacturer specifications state the supported input voltage, current draw, heat output and operating temperature and humidity range that the installation site must satisfy. Marketing material and informal notes are not controlled sources for these limits.

Question 32Installation, Setup, and Configuration

A new device ships with a well-known default administrator password. When should that password be changed?

  1. When the next scheduled maintenance window arrives
  2. Before the device is connected to the production network Correct answer.
  3. After the device has been running in production for one week
  4. Only if the device is exposed to the internet

Explanation

Factory default credentials are publicly documented, so any device reachable with them is effectively unauthenticated. The change belongs in staging, before the device is attached to production links.

Question 33Installation, Setup, and Configuration

Which practice makes a newly installed rack easier to troubleshoot later?

  1. Leaving spare length coiled inside the rack door
  2. Routing power and data cables through the same tray
  3. Bundling all cables of different types into one conduit
  4. Labelling both ends of every cable with a consistent scheme Correct answer.

Explanation

Consistent labelling at both ends lets a technician trace a connection without disturbing other cables or guessing. Separating power from data cabling and avoiding loose coils also reduce faults and interference.

Question 34Installation, Setup, and Configuration

Why should newly installed devices be pointed at a common time source such as NTP?

  1. It aligns timestamps so events can be correlated Correct answer.
  2. It encrypts the management traffic sent between devices
  3. It lowers the electrical power drawn by each appliance
  4. It reduces the storage space consumed by local log files

Explanation

Accurate, common time lets logs from different devices be ordered and matched during an incident. NTP has no effect on storage use, power draw or encryption.

Question 35Installation, Setup, and Configuration

What should you capture immediately before modifying the configuration of a working device?

  1. An export of the current running configuration Correct answer.
  2. A copy of the device's purchase invoice
  3. A list of the users currently logged in
  4. A screenshot of the device's status dashboard

Explanation

A configuration export gives a known-good state to restore if the change breaks service. Status screens and incidental records do not capture the full set of settings.

Question 36Installation, Setup, and Configuration

Which precaution protects circuit boards from damage while they are handled during installation?

  1. Working on a carpeted floor to cushion the board
  2. Wearing a wrist strap bonded to a grounded mat Correct answer.
  3. Storing boards in plain paper envelopes
  4. Holding the board by its edge connectors

Explanation

A wrist strap and grounded work surface keep the technician and the board at the same potential, preventing static discharge from damaging components. Carpet and paper generate and hold static charge.

Question 37Installation, Setup, and Configuration

After a device is installed, which record ties the physical unit to its role on the network?

  1. The packing slip that arrived with the shipped hardware
  2. An asset record with serial number and address Correct answer.
  3. The printed quick-start card included in the box
  4. The vendor's published end-of-life notice for the model

Explanation

An asset record is the controlled reference mapping serial number, hostname or address and physical location, so faults and changes can be traced to the right unit. Shipping paperwork and quick-start cards are not maintained after installation.

Question 38Installation, Setup, and Configuration

Which firmware release should a newly installed device run when it enters production?

  1. The release with the highest version number in the catalogue
  2. The newest build available on the vendor's download page
  3. The approved baseline release defined by your organisation Correct answer.
  4. Whichever release the device shipped with from the factory

Explanation

The approved baseline is the release the organisation has tested and supports, and it may deliberately lag the newest build. Factory firmware may contain known defects, and a higher version number is not automatically approved.

Question 39Installation, Setup, and Configuration

Why is a device's management interface often placed on a dedicated management VLAN?

  1. It automatically encrypts all traffic passing through the device
  2. It increases the throughput available to ordinary user sessions
  3. It removes the need to authenticate administrators
  4. It isolates administrative access from user traffic Correct answer.

Explanation

Separating management traffic onto its own segment restricts who can reach administrative interfaces and keeps that path independent of user-plane problems. It does not replace authentication or encryption.

Question 40Installation, Setup, and Configuration

A server must keep a fixed address, but the address range is managed centrally by DHCP. Which approach fits best?

  1. Create a DHCP reservation for the server's MAC address Correct answer.
  2. Configure the server to use link-local addressing
  3. Assign a static address from outside the managed range
  4. Let the server take any address the pool offers

Explanation

A reservation binds a specific address to the interface's hardware address, so the server always receives the same IP while the record stays under central control. A pool address can change, and an out-of-range static address bypasses the central record.

Question 41Installation, Setup, and Configuration

Before starting a configuration change in a maintenance window, what should be agreed with the stakeholders?

  1. The rollback method and the criteria for declaring success Correct answer.
  2. The names of the engineers who will be on call next month
  3. The purchase cost of any replacement hardware
  4. The exact make and model of every affected device

Explanation

A change is controlled when the team knows how to undo it and what evidence shows it worked. Without rollback steps and success criteria, a failed change turns into ad-hoc troubleshooting.

Question 42Installation, Setup, and Configuration

Why should each administrator have a named account rather than sharing a generic admin login?

  1. Shared accounts allow more granular role assignment
  2. Named accounts need fewer password resets
  3. Actions in the logs can be attributed to a specific person Correct answer.
  4. Named accounts reduce the number of licences required

Explanation

Individual accountability is the point: audit trails only deter and detect misuse when each action maps to one person. Roles and licences are managed separately from the naming decision.

Question 43Installation, Setup, and Configuration

What does an uninterruptible power supply provide to newly installed rack equipment?

  1. Protection against electrostatic discharge during servicing
  2. Ride-through during brief outages and time for an orderly shutdown Correct answer.
  3. Redundant network paths if a switch fails
  4. Conversion of DC input to the AC voltage the device expects

Explanation

A UPS carries the load through short interruptions and signals the device to shut down cleanly before the battery is exhausted. It does not convert DC to AC and plays no part in network redundancy.

Question 44Installation, Setup, and Configuration

Which practice preserves the cooling design of a rack after new equipment is mounted?

  1. Stacking units with no gap to increase airflow
  2. Leaving unused rack units open for extra ventilation
  3. Reversing the fans so all units blow toward the aisle
  4. Fitting blanking panels over unused rack units Correct answer.

Explanation

Open rack units let hot exhaust recirculate to the intake, so blanking panels keep the cold-air path intact. Fan direction should follow the manufacturer's design, and stacking units without gaps does not create airflow.

Question 45Installation, Setup, and Configuration

A switch port must carry traffic for several VLANs to another switch. How should the port be configured?

  1. As a mirrored port for the monitoring tool
  2. As a disabled port held in reserve
  3. As an access port assigned to the native VLAN
  4. As a trunk port carrying 802.1Q tags Correct answer.

Explanation

A trunk carries frames for multiple VLANs by adding an 802.1Q tag identifying the VLAN. An access port belongs to a single VLAN and cannot carry several.

Question 46Installation, Setup, and Configuration

The management page of a new device will be accessed from browsers. What should replace its self-signed certificate?

  1. A shared certificate copied from another device
  2. A self-signed certificate with a longer key
  3. An unencrypted HTTP listener on a non-standard port
  4. A trusted CA certificate naming the device's hostname Correct answer.

Explanation

Clients only accept a certificate silently when a trusted certificate authority has issued it and the name inside the certificate matches the address being used. A self-signed certificate, however long its key, still triggers warnings.

Question 47Installation, Setup, and Configuration

Which configuration sends a device's event records to a central collector for retention?

  1. Forwarding to a syslog server Correct answer.
  2. Raising the log buffer size on the device
  3. Enabling debug output on the console
  4. Turning on email alerts to the helpdesk

Explanation

Syslog forwarding transmits events to a remote host where they survive a device failure or reset and can be correlated with other sources. Local buffers and console output are lost or require manual capture.

Question 48Installation, Setup, and Configuration

Why apply an agreed naming convention to newly installed devices?

  1. It gives each device a unique, predictable identifier Correct answer.
  2. It encrypts the device's management sessions
  3. It guarantees the device will be patched on time
  4. It removes the need to document the network

Explanation

A convention encodes site, role and sequence so names stay unique and meaningful in inventory, monitoring and support tickets. It complements documentation rather than replacing it.

Question 49Installation, Setup, and Configuration

What provides evidence that a newly installed system is ready to be handed over to operations?

  1. A documented acceptance test with recorded results Correct answer.
  2. The vendor's datasheet listing supported features
  3. The installer's verbal assurance that it works
  4. A photograph of the completed rack installation

Explanation

Acceptance testing checks each agreed requirement and records the outcome so operations can confirm the system behaves as specified. Assurances, datasheets and photographs are not test evidence.

Question 50Installation, Setup, and Configuration

What should be verified when activating licences during installation?

  1. That every optional feature is enabled whether needed or not
  2. That entitled quantities match deployed capacity and are recorded Correct answer.
  3. That the licence keys are stored in the public documentation folder
  4. That activation waits until the first support case

Explanation

Licence entitlement must match what was actually deployed, or features may fail and support cover may be disputed; recording keys and counts completes the asset record. Keys should not be published, and unused features should be enabled deliberately.