Phototransistor Question & AnswersJune 18, 2022 By WatElectronics This article lists 100 Phototransistors MCQs for engineering students. All the Phototransistors Questions & Answers given below include a hint and a link wherever possible to the relevant topic. This is helpful for users who are preparing for their exams, interviews, or professionals who would like to brush up on the fundamentals of Phototransistors.The phototransistor is a bipolar or unipolar transistor. It is capable of converting light energy into electrical energy. It has a large base and collector width which is made using diffusion or ion implantation. Phototransistors available in both PNP and NPN types have different configurations like emitter, collector, and base. The device is activated once the light strikes the base terminal by allowing electron-hole pair configuration.They are available in two types: BJT and FET phototransistors. The output of a phototransistor depends on the wavelength of incident light. A phototransistor is more sensitive compared to a photodiode. Modes of operation are two types: Switch and Active modes. Switch mode works in the ON/OFF System. Active mode is also called linear which is proportional to light stimuli. Applications of phototransistors are counting, security systems, encoders, and light controls.Phototransistors depend on different parameters like Collector current, base current, dark current, peak wavelength, power dissipation, rise time, and fall time. Output response is very low. Available at low costs and relatively inexpensive.1). Phototransistor is a form of _____ transistor which is sensitive to light. Unipolar Bipolar Tripolar None of these HintRelating to two poles.2). Phototransistor which changes the ____ flowing between emitter and collector. Voltage Resistance Current All of the above HintStream of charged particles such as electrons.3). Phototransistors and ______ are used for sensing light. Transistors Amplifier Actuator Photodiodes HintMore complex than PN diode.4). Phototransistor is more _____ to gain from bipolar transistors. Destructive Sensitive Objective None of these HintWhich is quick to detect.5). Phototransistors are ____ used in several applications? Widely Loosely Tightly Coupling HintA large interval in between.6). Phototransistors are a form of the bipolar transistor which are ______ for light sensitivity. Improved Optimized Reduced Removed 7). Phototransistor is a very _____ electronic component available in the markets. Costly Rich Cheap None of these HintWhich is of little worth.8). Phototransistor development has been undertaken by _____? Bell Lab MIT radiator Lab Nasa Electric motors HintScientific development company.9). When the light touches the phototransistor the current ___ into the base region. Remains Constant Flow None Of these HintThe passage of something.10). Phototransistors are operated in _____ regions. Passive Hybrid Active All of the above HintWhich represents ready to engage.11). When light enters the base region of a phototransistor it generates an ________pair? Electron-Hole Emitter-Resistor Current-Voltage None Of these HintThe presence of two types of charge carriers.12). Electron-hole pair occurs in _____ biased CB junction. Forward Reverse Hybrid None of these HintWhich moves backward.13). Photodiode current is ______ by current gain of the transistor. Subtracted Added Multiplied Divided HintCause to increase in high quantity.14).Electron-hole pair generation is done under an _____ field. Magnetic Electric Electromagnetic None of these HintWhich is producing electricity.15). Phototransistor is incorporated under _____? Transistor Amplifier Integrated circuit None of these HintA set of electronic components on a small flat piece. Read more about Integrated circuit16). Phototransistor offers a reasonable ____? Temperature Speed Light Distance HintSomething which can move quickly.17). Phototransistors are easy _____ due to transient voltage spikes, and surges. Improved Damaged Available None of these HintPhysical harm on something.18). Phototransistors are classified into ____ types. One Two Three Four HintEven value.19). In a phototransistor, the base current is controlled by ____ light or infrared light. UV Visible LED LASER HintWhich can be seen.20). The operation range of a phototransistor depends on applied______ intensity? Light Flux Perceived High HintWhich is a bright form of energy.21). How many operating modes exist in phototransistors? 1 2 3 4 HintEven value.22). If there is no light in a phototransistor, then there is no flow of ____ in the transistor? Voltage Current Amplifier Inductance HintMeasured as net flow of electric charge.23). Does The switch-mode work in the _____ mode system? ON/OFF Zero High True HintHaving two positions.24). Active mode is called linear which is _____ toward the light stimuli. Against Proportional Available Due HintHaving a constant ratio to another quantity.25). Due to low-level intensity, phototransistors provide current gain which is equal to ___ transistors? One Two Three None of these HintWhich represents a dual role.Phototransistors MCQs for Quiz26). Sensitivity of the phototransistor depends on the type of selected ______ used? Functions Types Materials Methods HintA mixture of substances that constituents an object.27). For Silicon material, the electromagnetic wavelength range is 190 to ____nm. 1000 1100 1200 1300 HintMid value.28). For Germanium material, the electromagnetic wavelength range is ___ to 1700nm. 200 300 400 500 HintMid value.29). For Indium gallium arsenide material, the electromagnetic wavelength range is ___ to 2600nm. 200 400 600 800 HintWhich represents the difference of 1000-200 values.30). For proper functioning of phototransistors ____ technology is used. High-Level Mounting Low-Level Hybrid HintSomething serving as support.31). For Lead sulfide material, the electromagnetic wavelength range is ___ than 1000nm. More Equal Less Hybrid HintA smaller amount of something.32).Normal phototransistors are designed using _____? Si Ge InGaAs PbS HintA nonmetallic chemical element.33). SMT Stands for ______? Soldering mount technology Surface mount technology Seize mart technology None of these HintElectric components are directly mounted on the surface..34).THT stands for ______? Transistor high test Transistor high technic Through-hole technology Through high transistor HintHoles are drilled on the circuit board.35). Phototransistors include a ____ filter, which is used to block observable light. High Pass Low Pass Cut Off Band Pass HintTo bring to ultimately end.36).Light detection is improved by ____ coating. Reflective Anti-Reflective Surface Plastic HintCoated with transparent film.37). The output of a phototransistor depends on the _____ of incident light. Bandwidth Temperature Frequency Wavelength HintDistance between two identical points.38). _____ detects the presence of an object by generating the light. Optical Switch Retro Sensor Optoisolator None Of these HintThis is a type of photoelectric sensor.39)._____ is the same as a transformer in which output is electrically isolated from the input. Optical Switch Retro Sensor Optoisolator None Of these HintWhich is also called optocoupler.40). Phototransistor which converts ____ energy into electrical energy. Light Water Volume High HintElectromagnetic spectrum viewed by the human eye.41). The output response of a phototransistor is very ____? High Low Medium None of these HintWhich is less to an extent.42). Phototransistor has ____ dark current. Less High Medium None of these HintWhich is up to a maximum extent.43). Only ____ biasing is used in phototransistors. Reverse Hybrid Forward Normal HintDirection facing towards the front.44). Linear response range of a phototransistor is very ____? Low High Medium None Of These HintWhich is least concerning.45). Phototransistors symbol has two ___ which indicates the light incident. Arrows Marks Dots Circles HintUsed to indicate direction.46). In phototransistors, the base to collector junction size is _____ due to light sensitivity. Lower Higher Medium Null HintThe more advanced ones.47). Size of junction determines better junction _____? Inductance Resistance Capacitance Voltage HintThe amount of electric charge stored on the conductor.48). Phototransistor has a ____ frequency response compared to photodiodes. High Less Medium None of these HintWhich is not so much.49). Best example of a phototransistor IC is ____? 2N5777 3N5777 4N5777 6N5777 HintWhich represents the least even value starting.50). After complete setup the phototransistor is placed in a ____ box. Square Empty Metallic Filled HintWhich is related to metals.Phototransistors MCQs for Students51). ___ is placed at the top of the metallic box to absorb incident radiation. Tube Lens Wire Cathode HintWhich is a transparent material.52). Magnitude of current _____ along with the intensity of light. Decreases Moves Applies Increases HintWhich is the rise in size.53). Collector current is supplied in a phototransistor using ___ dimensions. MA mA kA 0.1A HintCurrent equal to thousand of an ampere.54). Noise ____ is more immune to phototransistors. Making Interference Suitable Remains HintWhich is a disturbance.55). Peak wavelength value of phototransistor is ____nm. 900 920 940 1098 HintWhich represents a difference of 1000-60.56). The maximum power supplied to the phototransistor is ____W. 10m 100m 1000m 1m HintWhich is a multiple of 10 and 10.57). Maximum current allowed up to ___nA to run a phototransistor. 10 1 100 1000 HintWhich is a century.58). The viewing angle difference in phototransistors is ____ degrees. 10 20 30 40 HintMid value.59). Maximum breakdown voltage is ____ in VCE. 20V 10V 9V 3V HintWhich is a difference of 50-30 values.60). Frequent occurrence of _____ surges takes place in phototransistors. Electromagnetic Magnetic Electric Hybrid HintWhich charges the materials.61). _________ is defined as the ratio of photoelectric current to incident luminous flux. Luminous reactivity Luminous sensitivity Reflection Refraction HintWhich response to bright color.62). _____ is used as the sensitivity of phototransistors which is a function of wavelength. Frequency response Spectral Response Time Response Wavelength HintRelative efficiency of deflection.63).____gain indicates the efficiency of converting light into electrical energy. Electric Magnetic Photoelectric Photosensitivity HintIn which electrically charged particles are released.64). Speed of response is ____ proportional to phototransistor gain. Directly Inversely Immediate Continuous HintWhich represents oppositely.65). Phototransistors are less noisy compared to _____ photodiodes. Schottky Avalanche PN PIN HintOccurs in insulators and semi-conductors.66)._____ are affected by electromagnetic energy. Transistors Amplifiers Phototransistors Diodes HintWhere light can reach the base.67). Output of phototransistors depends on the area of CB Junction, wavelength, and DC___ of the transistor. Voltage gain Current gain Resistivity Conductivity HintChange in collector current to emitter current.68). A small reverse saturation current flow is called ___ current. High Low Light Dark HintWhich represents no light.69). Phototransistors can be prone to ____ damage due to voltage breakdown. Temporary Permanent Compulsory Relevant HintWhich remains unchanged indefinitely.70). In ____ transistors, the entire device is made up of single material. Hetero Junction Multi-Junction Homo Junction None Of these HintWhich represents a single.71)._____ can be converted into a phototransistor by removing emitter terminals. Collector Emitter Photodiode Photoresistor HintSemiconductor device which is exposed to light.72). In photodarlington, the ____ induces much more power i.e, sensitivity rises. Photodiode Photoresistor Phototransistor None of these HintEmitter and collector current increases.73)._____ contains a phototransistor that is activated by an internal LED device. Decoupler Tricoupler Heptacoupler Optocoupler HintTransfers electrical signal between isolated circuits. Read more about LED .74). Phototransistor is interfaced with ____ containing ADC. MC MP Oscillator Amplifier HintWhich embeds all electronic components.75). With slight modifications to the Light-operated relay circuit which can implement ____? Dark current Darkness operated relay Relay switch None of these HintWithout no light focus on the switch.Phototransistors MCQs for Interviews76). When the intensity of light is less, then the phototransistor is in ___ mode. Active Off Switch Alter HintWhich is the unstable mode.77). Phototransistor works on the principle of _____ effect. Photoelectric Photomagnetic Diffusion None of these HintEmission of electrons from the surface.78). Phototransistors widely find their applications in ____ readers. Memory Punch Card Closed-Circuit Open Circuit HintA card perforated according to code.79). Phototransistors are effectively utilized in _____ systems. Circuit Counting Reader Edge HintWhich counts the whole system.80). The device which converts one energy to another energy is called____? Operator Transducer Amplifier Adder HintVariations in physical quantity.81). If the wavelength is increased, then the _____ will be decreased. Time Frequency Voltage Current HintWhich represents a particular period.82). As the base current increases, the illumination level also ___? Increases Decreases Removes None of these HintMake it greater in size.83). The circuitry of this type is ____ complicated. High Less Null None of these HintMake it lower in size.84). At high frequencies, phototransistors don't ___ properly. Stop Work Stable Remains HintTasks to be undertaken.85). Effective resistances have ____ fluctuates with temperature variations. High Less More Increased HintWhich is of lower rank.86). Hetero structures use different materials at PN, and it produces a high ____efficiency. Conversion Amplification Comparison None of these HintChanging from one method to another.87). Homostructures use a ___ material throughout the semiconductor device. Different Same Above High HintWhich represents a similar one.88). Phototransistors cannot handle high voltages like ____? Transistors Photodiode Photo Thyristor Amplifiers HintUsed in photography as flashes.89).Units of light intensity are ____? mW/m^2. mW/cm^2 W/m^2 W/cm^2 HintWhich represents watts in 10^-3.90). Phototransistors generate only ___? Voltage Current Inductance Resistance HintPassage or movement of electrons.91). Phototransistors are sensitive to _____ light sources like sunlight, fluorescent, and lasers. Same Different Unique None of these HintWhich is unlike in nature.92).Phototransistors are _____ reliable. Less Highly Least None of these HintWhich is a high degree.93). Phototransistors are ____ stable. Permanently Unique Temporarily None of these HintWhich is a limited period.94). Phototransistors are available in ____ packages. Same Different Hybrid None of these HintWhich is very distinct/separate.95).Phototransistors are used in _____ detectors. Vibration Perimeter Smoke Proximity HintWhich is in the presence of time.96). Most widely used applications of phototransistors are ____? Regenerate systems Counting systems High systems Low-level systems HintWhich is taken into account.97). A small is placed at the surface of ____ junction to place the lens. EB CB NPN PN HintWhich represents the collector base.98). Basically, phototransistors do not have a ___ connection? Emitter Base Collector Terminals HintWhich is the lowest part of the edge.99)._____ cannot generate a voltage. Photoresistors Photoreceptors Photodiodes Phototransistors HintAn organism that responds to light.100). Phototransistors are used in ___ to measure speed and direction. Decoder Encoder Divider Multiplier HintConverts data into other formats.For More MCQsField Effect Transistor Questions & AnswersTransistors Questions & Answers Please fill in the comment box below. Time is Up! Time's up
