Phototransistor Question & Answers June 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 None Hint 2). Phototransistor which changes the ____ flowing between emitter and collector. Voltage Resistance Current All of the above None Hint 3). Phototransistors and ______ are used for sensing light. Transistors Amplifier Actuator Photodiodes None Hint 4). Phototransistor is more _____ to gain from bipolar transistors. Destructive Sensitive Objective None of these None Hint 5). Phototransistors are ____ used in several applications? Widely Loosely Tightly Coupling None Hint 6). Phototransistors are a form of the bipolar transistor which are ______ for light sensitivity. Improved Optimized Reduced Removed None 7). Phototransistor is a very _____ electronic component available in the markets. Costly Rich Cheap None of these None Hint 8). Phototransistor development has been undertaken by _____? Bell Lab MIT radiator Lab Nasa Electric motors None Hint 9). When the light touches the phototransistor the current ___ into the base region. Remains Constant Flow None Of these None Hint 10). Phototransistors are operated in _____ regions. Passive Hybrid Active All of the above None Hint 11). When light enters the base region of a phototransistor it generates an ________pair? Electron-Hole Emitter-Resistor Current-Voltage None Of these None Hint 12). Electron-hole pair occurs in _____ biased CB junction. Forward Reverse Hybrid None of these None Hint 13). Photodiode current is ______ by current gain of the transistor. Subtracted Added Multiplied Divided None Hint 14).Electron-hole pair generation is done under an _____ field. Magnetic Electric Electromagnetic None of these None Hint 15). Phototransistor is incorporated under _____? Transistor Amplifier Integrated circuit None of these None Hint Read more about Integrated circuit 16). Phototransistor offers a reasonable ____? Temperature Speed Light Distance None Hint 17). Phototransistors are easy _____ due to transient voltage spikes, and surges. Improved Damaged Available None of these None Hint 18). Phototransistors are classified into ____ types. One Two Three Four None Hint 19). In a phototransistor, the base current is controlled by ____ light or infrared light. UV Visible LED LASER None Hint 20). The operation range of a phototransistor depends on applied______ intensity? Light Flux Perceived High None Hint 21). How many operating modes exist in phototransistors? 1 2 3 4 None Hint 22). If there is no light in a phototransistor, then there is no flow of ____ in the transistor? Voltage Current Amplifier Inductance None Hint 23). Does The switch-mode work in the _____ mode system? ON/OFF Zero High True None Hint 24). Active mode is called linear which is _____ toward the light stimuli. Against Proportional Available Due None Hint 25). Due to low-level intensity, phototransistors provide current gain which is equal to ___ transistors? One Two Three None of these None Hint Phototransistors MCQs for Quiz 26). Sensitivity of the phototransistor depends on the type of selected ______ used? Functions Types Materials Methods None Hint 27). For Silicon material, the electromagnetic wavelength range is 190 to ____nm. 1000 1100 1200 1300 None Hint 28). For Germanium material, the electromagnetic wavelength range is ___ to 1700nm. 200 300 400 500 None Hint 29). For Indium gallium arsenide material, the electromagnetic wavelength range is ___ to 2600nm. 200 400 600 800 None Hint 30). For proper functioning of phototransistors ____ technology is used. High-Level Mounting Low-Level Hybrid None Hint 31). For Lead sulfide material, the electromagnetic wavelength range is ___ than 1000nm. More Equal Less Hybrid None Hint 32).Normal phototransistors are designed using _____? Si Ge InGaAs PbS None Hint 33). SMT Stands for ______? Soldering mount technology Surface mount technology Seize mart technology None of these None Hint 34).THT stands for ______? Transistor high test Transistor high technic Through-hole technology Through high transistor None Hint 35). Phototransistors include a ____ filter, which is used to block observable light. High Pass Low Pass Cut Off Band Pass None Hint 36).Light detection is improved by ____ coating. Reflective Anti-Reflective Surface Plastic None Hint 37). The output of a phototransistor depends on the _____ of incident light. Bandwidth Temperature Frequency Wavelength None Hint 38). _____ detects the presence of an object by generating the light. Optical Switch Retro Sensor Optoisolator None Of these None Hint 39)._____ is the same as a transformer in which output is electrically isolated from the input. Optical Switch Retro Sensor Optoisolator None Of these None Hint 40). Phototransistor which converts ____ energy into electrical energy. Light Water Volume High None Hint 41). The output response of a phototransistor is very ____? High Low Medium None of these None Hint 42). Phototransistor has ____ dark current. Less High Medium None of these None Hint 43). Only ____ biasing is used in phototransistors. Reverse Hybrid Forward Normal None Hint 44). Linear response range of a phototransistor is very ____? Low High Medium None Of These None Hint 45). Phototransistors symbol has two ___ which indicates the light incident. Arrows Marks Dots Circles None Hint 46). In phototransistors, the base to collector junction size is _____ due to light sensitivity. Lower Higher Medium Null None Hint 47). Size of junction determines better junction _____? Inductance Resistance Capacitance Voltage None Hint 48). Phototransistor has a ____ frequency response compared to photodiodes. High Less Medium None of these None Hint 49). Best example of a phototransistor IC is ____? 2N5777 3N5777 4N5777 6N5777 None Hint 50). After complete setup the phototransistor is placed in a ____ box. Square Empty Metallic Filled None Hint Phototransistors MCQs for Students 51). ___ is placed at the top of the metallic box to absorb incident radiation. Tube Lens Wire Cathode None Hint 52). Magnitude of current _____ along with the intensity of light. Decreases Moves Applies Increases None Hint 53). Collector current is supplied in a phototransistor using ___ dimensions. MA mA kA 0.1A None Hint 54). Noise ____ is more immune to phototransistors. Making Interference Suitable Remains None Hint 55). Peak wavelength value of phototransistor is ____nm. 900 920 940 1098 None Hint 56). The maximum power supplied to the phototransistor is ____W. 10m 100m 1000m 1m None Hint 57). Maximum current allowed up to ___nA to run a phototransistor. 10 1 100 1000 None Hint 58). The viewing angle difference in phototransistors is ____ degrees. 10 20 30 40 None Hint 59). Maximum breakdown voltage is ____ in VCE. 20V 10V 9V 3V None Hint 60). Frequent occurrence of _____ surges takes place in phototransistors. Electromagnetic Magnetic Electric Hybrid None Hint 61). _________ is defined as the ratio of photoelectric current to incident luminous flux. Luminous reactivity Luminous sensitivity Reflection Refraction None Hint 62). _____ is used as the sensitivity of phototransistors which is a function of wavelength. Frequency response Spectral Response Time Response Wavelength None Hint 63).____gain indicates the efficiency of converting light into electrical energy. Electric Magnetic Photoelectric Photosensitivity None Hint 64). Speed of response is ____ proportional to phototransistor gain. Directly Inversely Immediate Continuous None Hint 65). Phototransistors are less noisy compared to _____ photodiodes. Schottky Avalanche PN PIN None Hint 66)._____ are affected by electromagnetic energy. Transistors Amplifiers Phototransistors Diodes None Hint 67). Output of phototransistors depends on the area of CB Junction, wavelength, and DC___ of the transistor. Voltage gain Current gain Resistivity Conductivity None Hint 68). A small reverse saturation current flow is called ___ current. High Low Light Dark None Hint 69). Phototransistors can be prone to ____ damage due to voltage breakdown. Temporary Permanent Compulsory Relevant None Hint 70). In ____ transistors, the entire device is made up of single material. Hetero Junction Multi-Junction Homo Junction None Of these None Hint 71)._____ can be converted into a phototransistor by removing emitter terminals. Collector Emitter Photodiode Photoresistor None Hint 72). In photodarlington, the ____ induces much more power i.e, sensitivity rises. Photodiode Photoresistor Phototransistor None of these None Hint 73)._____ contains a phototransistor that is activated by an internal LED device. Decoupler Tricoupler Heptacoupler Optocoupler None Hint Read more about LED . 74). Phototransistor is interfaced with ____ containing ADC. MC MP Oscillator Amplifier None Hint 75). With slight modifications to the Light-operated relay circuit which can implement ____? Dark current Darkness operated relay Relay switch None of these None Hint Phototransistors MCQs for Interviews 76). When the intensity of light is less, then the phototransistor is in ___ mode. Active Off Switch Alter None Hint 77). Phototransistor works on the principle of _____ effect. Photoelectric Photomagnetic Diffusion None of these None Hint 78). Phototransistors widely find their applications in ____ readers. Memory Punch Card Closed-Circuit Open Circuit None Hint 79). Phototransistors are effectively utilized in _____ systems. Circuit Counting Reader Edge None Hint 80). The device which converts one energy to another energy is called____? Operator Transducer Amplifier Adder None Hint 81). If the wavelength is increased, then the _____ will be decreased. Time Frequency Voltage Current None Hint 82). As the base current increases, the illumination level also ___? Increases Decreases Removes None of these None Hint 83). The circuitry of this type is ____ complicated. High Less Null None of these None Hint 84). At high frequencies, phototransistors don't ___ properly. Stop Work Stable Remains None Hint 85). Effective resistances have ____ fluctuates with temperature variations. High Less More Increased None Hint 86). Hetero structures use different materials at PN, and it produces a high ____efficiency. Conversion Amplification Comparison None of these None Hint 87). Homostructures use a ___ material throughout the semiconductor device. Different Same Above High None Hint 88). Phototransistors cannot handle high voltages like ____? Transistors Photodiode Photo Thyristor Amplifiers None Hint 89).Units of light intensity are ____? mW/m^2. mW/cm^2 W/m^2 W/cm^2 None Hint 90). Phototransistors generate only ___? Voltage Current Inductance Resistance None Hint 91). Phototransistors are sensitive to _____ light sources like sunlight, fluorescent, and lasers. Same Different Unique None of these None Hint 92).Phototransistors are _____ reliable. Less Highly Least None of these None Hint 93). Phototransistors are ____ stable. Permanently Unique Temporarily None of these None Hint 94). Phototransistors are available in ____ packages. Same Different Hybrid None of these None Hint 95).Phototransistors are used in _____ detectors. Vibration Perimeter Smoke Proximity None Hint 96). Most widely used applications of phototransistors are ____? Regenerate systems Counting systems High systems Low-level systems None Hint 97). A small is placed at the surface of ____ junction to place the lens. EB CB NPN PN None Hint 98). Basically, phototransistors do not have a ___ connection? Emitter Base Collector Terminals None Hint 99)._____ cannot generate a voltage. Photoresistors Photoreceptors Photodiodes Phototransistors None Hint 100). Phototransistors are used in ___ to measure speed and direction. Decoder Encoder Divider Multiplier None Hint For More MCQs Field Effect Transistor Questions & Answers Transistors Questions & Answers Please fill in the comment box below. Time's up
