Information and Communication Technology

How many input lines are there in the NOT gate ?

[amp_mcq option1=”2″ option2=”1″ option3=”3″ option4=”4″ correct=”option2″]

A NOT gate, also known as an inverter, is a basic digital logic gate that performs logical negation. It takes a single binary input and produces an output that is the opposite logic level (0 becomes 1, and 1 becomes 0). Therefore, it has exactly one input line.

The NOT gate is a unary operation, meaning it operates on a single input.

Other basic logic gates like AND, OR, XOR, NAND, and NOR typically have two or more input lines. The output of a NOT gate is always the complement of its input.

How many bits combination is present in a Byte?

[amp_mcq option1=”2″ option2=”4″ option3=”8″ option4=”16″ correct=”option3″]

A byte is the fundamental unit of data storage in computer systems, typically defined as a sequence of 8 bits.

A byte consists of 8 bits, which is the smallest addressable unit of memory for most modern computer architectures.

A bit is the smallest unit of data, representing a binary value (0 or 1). A group of 4 bits is called a nibble. Larger units include words, which consist of varying numbers of bytes depending on the computer architecture (e.g., 2 bytes for a 16-bit word, 4 bytes for a 32-bit word, 8 bytes for a 64-bit word).

1 KB is equivalent to :

[amp_mcq option1=”1042 bytes.” option2=”1023 bytes.” option3=”1021 bytes.” option4=”1024 bytes.” correct=”option4″]

In the context of computer memory and storage, 1 KB (Kilobyte) is conventionally understood as 2¹⁰ bytes.

The standard definition of a Kilobyte in computing is 1024 bytes, based on powers of 2 (2¹⁰).

While the SI definition of kilo (k) is 10³ (1000), computer science traditionally uses powers of 2. This led to ambiguity, and standards bodies like IEC introduced prefixes like kibi (Ki) for 2¹⁰ (1024) and kilo (k) for 10³ (1000). However, in common usage for memory sizes, KB still widely refers to 1024 bytes. For storage devices like hard drives and network speeds, kilo often means 1000. Given the options, 1024 is the expected answer for a computer science context.

Which one of the following is a sequential electronic circuit that is used to store 1-bit information?

[amp_mcq option1=”Register” option2=”Flip-flop” option3=”Counter” option4=”Accumulator” correct=”option2″]

A flip-flop is a basic sequential logic circuit that has two stable states and can store one bit of binary information (0 or 1). It is the fundamental building block for memory elements in digital electronics.

Flip-flops are the elementary memory units in sequential circuits, capable of storing a single bit of data and changing state based on input signals and clock pulses.

A register is a collection of multiple flip-flops used to store a group of bits (e.g., a byte or a word). A counter is a sequential circuit that cycles through a sequence of states, often counting pulses, and is typically constructed using flip-flops. An accumulator is a type of register used in central processing units (CPUs) for performing arithmetic and logic operations.

Which of the following is/are the basic function(s) of a CCTV system ?

• 1. To disallow unauthorised persons to enter into any building in the premises
• 2. To allow a person to observe a scene without being present at the scene
• 3. To allow an activity to be recorded for future viewing

Select the correct answer using the code given below :

[amp_mcq option1=”1, 2 and 3″ option2=”2 only” option3=”1 and 3 only” option4=”2 and 3 only” correct=”option4″]

The correct answer is D) 2 and 3 only. The basic functions of a CCTV system are to allow remote observation of a scene and to record activities for later review.

– Statement 1 is incorrect because a CCTV system is a surveillance tool; it monitors and records but does not physically prevent unauthorized entry. Access control systems (like locks, turnstiles, card readers) perform the function of disallowing entry.
– Statement 2 is correct. The primary purpose of CCTV is to transmit video from cameras at one location to monitors at another, allowing personnel to observe a scene remotely.
– Statement 3 is correct. Recording video footage is a standard and essential function of modern CCTV systems, allowing for investigation of incidents, monitoring trends, and evidence collection.

CCTV (Closed-Circuit Television) systems are widely used for security, surveillance, and monitoring in various environments like public places, buildings, traffic management, etc. While CCTV is often part of a larger security system that might include access control or alarms, its fundamental functions are remote viewing and recording.

Metal detector is meant to detect the presence of which of the following in the search object ?

[amp_mcq option1=”Ferrous metal only” option2=”Ferrous and plastic objects only” option3=”Ferrous and non-ferrous objects only” option4=”Ferrous, non-ferrous and plastic objects” correct=”option3″]

The correct answer is C) Ferrous and non-ferrous objects only. Standard metal detectors operate by detecting disruptions in an electromagnetic field caused by conductive materials, which include both ferrous metals (containing iron) and non-ferrous metals (like aluminum, copper, gold, silver).

– Metal detectors work on the principle of electromagnetism. They emit an electromagnetic field and detect the presence of metal objects by measuring the secondary magnetic field induced in the object or the change in the primary field.
– Ferrous metals are magnetic (e.g., iron, steel), while non-ferrous metals are not magnetic but are still conductive (e.g., aluminum, copper, brass, gold). Both types interact with the electromagnetic field of a metal detector.
– Plastic is not a conductive material and therefore does not interfere with the electromagnetic field in a way that a standard metal detector can detect.

While standard walk-through and hand-held metal detectors detect metals, other security screening technologies exist to detect non-metallic objects like plastics, ceramics, liquids, or explosives, such as X-ray scanners, body scanners (using millimetre wave or backscatter technology), and trace detection portals.

Night Vision Devices do not consist of :

[amp_mcq option1=”Telescope.” option2=”Binocular.” option3=”X-rays.” option4=”Infrared image converter tube.” correct=”option3″]

Night Vision Devices work by either amplifying existing ambient light (using image intensifier tubes which often include IR converters) or by detecting infrared radiation (thermal imaging). They use optical components similar to telescopes and are often built into binocular form factors. X-rays are a different part of the electromagnetic spectrum and are not used or detected by standard night vision technology. X-ray detection requires entirely different types of sensors and is used for applications like medical imaging or security screening.

– Night vision uses light amplification (visible/IR) or thermal detection (IR).
– Optical components like lenses (related to telescopes/binoculars) are essential.
– Image intensifier tubes process low light/IR into visible images.
– X-rays are not within the spectrum or mechanism used by typical night vision devices.

Night vision typically operates in the visible light spectrum (for amplification) and the infrared spectrum (for amplification or thermal imaging). X-rays are high-energy electromagnetic radiation and are not involved in the functioning of standard night vision equipment.

Which one of the following is not detected by fire detectors ?

[amp_mcq option1=”Radiation” option2=”Heat” option3=”Light” option4=”Smoke” correct=”option1″]

Fire detectors are designed to detect signs of fire: Smoke, Heat, or specific types of Radiation (like UV or Infrared) emitted by flames. Standard fire detectors do not typically detect other forms of radiation, such as X-rays or nuclear radiation, which are not characteristics of a typical fire. While flame detectors detect UV/IR radiation from the fire itself, the term ‘Radiation’ alone is broad and can encompass types not related to fire. Given the other options (Heat, Light, Smoke) are directly detected by common types of fire detectors (heat detectors, smoke detectors, flame detectors), ‘Radiation’, interpreted broadly (e.g., X-rays), is the phenomenon not typically detected by fire detectors.

– Fire detection methods include sensing smoke, heat, and flame.
– Flame detectors specifically detect UV and IR radiation from flames.
– Standard fire detectors do not detect other forms of radiation like X-rays or nuclear radiation.

Common types of fire detectors are smoke detectors (ionization and photoelectric), heat detectors (fixed temperature and rate-of-rise), and flame detectors (UV, IR, or UV/IR). While ‘Light’ could refer to visible light (less common for primary detection than UV/IR), and ‘Radiation’ specifically refers to the UV/IR detected by flame detectors, the option ‘Radiation’ alone is broad enough to include types not related to fire, making it the least likely phenomenon detected by *fire* detectors in a general sense. Assuming ‘Radiation’ is not limited to UV/IR from flame, it is the correct answer.

Which one of the following is not a function of Personnel Access Control System ?

[amp_mcq option1=”To prepare Identity Card” option2=”To interrogate” option3=”To take decisions” option4=”To respond” correct=”option1″]

A Personnel Access Control System is designed to control who can access specific areas based on predefined rules and credentials. Its functions include interrogating the credential presented (e.g., reading a card or biometric scan), deciding whether access should be granted or denied based on the person’s identity and permissions, and responding by activating a lock, triggering an alarm, or logging the event. However, the system itself does not typically *prepare* or issue the physical identity cards or credentials; that is usually a separate administrative or security function managed by a different system or department (like HR or a dedicated badging system).

– Access Control Systems verify identities and permissions.
– Core functions include reading credentials (interrogate), checking rules (decide), and enabling/denying access (respond).
– The creation or issuance of identity cards is separate from the access control *system’s* real-time function.

Access Control Systems manage databases of individuals and their access levels, but the physical process of designing, printing, and issuing ID cards is typically handled by dedicated identity management software or manual processes outside the core access control transaction processing.

Card reader as a means of Access Control is becoming popular as compared to a human guard. In this context, which one of the following statements is not correct ?

[amp_mcq option1=”It offers better security as it cannot be bribed.” option2=”It is more economical.” option3=”It can never fail.” option4=”It is always alert.” correct=”option3″]

Statement C, “It can never fail,” is not correct. Electronic systems, including card readers for access control, are subject to potential failures. These can include technical glitches, power outages, software errors, network issues, or physical damage to the reader or the card. While generally reliable, stating they can *never* fail is inaccurate.

– Card readers are electronic access control devices.
– Electronic systems are susceptible to various forms of failure (technical, power, software).
– Human guards have different failure modes (bribed, distracted, tired) compared to electronic systems.

Statements A, B, and D highlight advantages of automated access control: being incorruptible (A), potentially more economical in the long run (B), and consistently vigilant (D), compared to human guards. However, the possibility of technical failure remains a reality for electronic systems.