Zener Photodiode LED & Solar Cell — Practice Questions

Free NEET Physics multiple-choice questions on Zener Photodiode LED & Solar Cell. Attempt each question and reveal the answer with a full explanation.

A Zener diode with V Z = 6 V is used in a circuit. If the maximum power dissipation allowed is 300 mW , the maximum Zener current I Z,max is: 50 mA 1.8 mA 18 mA 0.05 mA An LED is made of a semiconductor with a band gap of 2.0 eV . The wavelength of the light emitted is approximately: 6200 4000 8000 5000 A Zener diode is designed to operate in: The breakdown region under reverse bias The saturation region under forward bias The cut-off region The linear region under forward bias A Zener diode is specified with a Zener voltage V Z = 5.0 V and a maximum power dissipation P max = 250 mW . What is the maximum Zener current I Z(max) it can handle? 50 mA 1.25 A 25 mA 250 mA The 'Dark Current' in a photodiode refers to: The current that flows when no light is incident on the diode The current generated by black light The maximum current at saturation The current due to recombination of electrons A photodiode is fabricated from a semiconductor with a band gap of 2.5 eV . It can detect a signal of wavelength: 4000 00c5 6000 00c5 5000 00c5 5500 00c5 An LED is constructed from a GaP semiconductor with E g = 2.26 eV . The color of the light emitted is: Green Red Yellow Violet The characteristic curve of a solar cell is represented by which of the following graphs? A graph in the fourth quadrant showing current vs voltage. A linear graph passing through the origin. A graph in the first quadrant with current increasing with voltage. A horizontal line at constant current. For a solar cell, the V-I characteristics are usually drawn in the fourth quadrant because: The cell supplies power to the load The cell consumes power from the circuit The resistance of the cell is negative The current flows from n to p side inside the cell The reverse breakdown in a Zener diode is primarily due to: High electric field Impact ionization Thermal instability Diffusion of minority carriers Which of the following materials is preferred for making a solar cell? GaAs PbS C (Diamond) Ge Which type of diode is used to generate a constant reference voltage in electronic circuits? Zener diode Varactor diode Tunnel diode PIN diode The reverse breakdown of a p-n junction due to the high electric field pulling electrons directly out of the covalent bonds is known as: Zener breakdown Avalanche breakdown Thermal runaway Recombination A photodiode is preferably operated in reverse bias mode because: The fractional change in minority carrier current is much higher than that in majority carrier current The reverse current is much larger than the forward current The depletion width decreases, allowing more light to enter The response time is significantly increased For a Zener diode used as a voltage regulator, the series resistance R S is essential to: Limit the Zener current within its power rating Increase the breakdown voltage of the diode Ensure the diode remains in the forward bias region Decrease the load current Which of the following materials is most suitable for fabrication of a solar cell that needs to match the solar spectrum? GaAs Si CdS PbS Consider the following statements (A) and (B) and identify the correct answer. (A) A Zener diode is always connected in reverse bias. (B) The potential barrier of a p-n junction lies between 0.1 to 0.3 V for Germanium. Both (A) and (B) are correct (A) is correct but (B) is incorrect (A) is incorrect but (B) is correct Both (A) and (B) are incorrect Which of the following diode types exhibits a 'negative resistance' region in its V-I characteristic? Tunnel diode Zener diode Photodiode LED A solar cell is made from a material with a bandgap of 1.4 eV . The open-circuit voltage ( V oc ) of this cell is typically: Less than 1.4 V Exactly 1.4 V Greater than 1.4 V Independent of the bandgap In the context of optoelectronics, why are direct band gap semiconductors like GaAs preferred over indirect band gap semiconductors like Si for manufacturing LEDs? Recombination of carriers occurs primarily through photon emission They have a higher thermal conductivity They are easier to dope with p-type impurities They have a much smaller band gap A solar cell is usually made from Silicon rather than Germanium because: Silicon has a better match with the solar spectrum energy peaks Germanium has a higher band gap Silicon is a better conductor of electricity Germanium reacts with sunlight to produce heat The 'Fill Factor' (FF) of a solar cell is defined as the ratio of: P max / (V oc I sc ) V oc / I sc P max / P in (V oc I sc ) / P max In a Zener diode regulator, the Zener diode must be operated in the: Breakdown region Active region Cut-off region Saturation region A Tunnel Diode is characterized by which unique feature in its V-I curve? A region of negative differential resistance An extremely high breakdown voltage No reverse saturation current A linear relationship between V and I The dynamic impedance of a Zener diode in the breakdown region is ideally: Zero Infinite Equal to the load resistance Negative A Zener diode, having breakdown voltage equal to 15 V , is used in a voltage regulator circuit. If the unregulated input is 20 V , and the series resistance is 250 , what is the current through the Zener diode if the load resistance is 1 k ? 5 mA 20 mA 15 mA 10 mA A Zener diode is used as a voltage regulator. If the input unregulated voltage increases, the Zener current ( I Z ) and the load current ( I L ) change as follows: I Z increases, I L remains constant I Z remains constant, I L increases Both I Z and I L increase Both I Z and I L remain constant Which type of diode has a very thin depletion layer such that electrons can cross the barrier via quantum mechanical tunneling? Tunnel Diode Zener Diode Varactor Diode Schottky Diode A Zener diode has a contact potential of 0.8 V in the absence of biasing. It undergoes Zener breakdown at an electric field of 10 6 V/m at the junction. If the width of the depletion region is 2 m , the Zener voltage is: 1.2 V 2.0 V 0.8 V 2.8 V An ideal Zener diode with breakdown voltage of -3 V is reverse biased with a negative input voltage V i=-5 V. The magnitude of voltage difference between point B and A is: 3 V 2 V 1 V 0 V A Zener diode is used for: Voltage regulation Rectification Amplification Producing oscillations An LED (Light Emitting Diode) is: Forward biased Reverse biased Not biased Biased in breakdown region A photodiode is a semiconductor device that: Is always used in reverse bias Is always used in forward bias Converts electrical energy into light Has a very low resistance in the dark Which type of diode is primarily designed to operate in the reverse breakdown region without being damaged? Zener Diode Varactor Diode Light Emitting Diode Tunnel Diode A solar cell works on the principle of: Photovoltaic effect Thermionic emission Photoelectric effect Seebeck effect A Zener diode is specified as having a breakdown voltage of 9.1 V with a maximum power dissipation of 364 mW . What is the maximum current the diode can handle? 40 mA 20 mA 50 mA 33 mA