How Well Do You Know Photodiode Quiz

1. When a photon of sufficient energy strikes the diode, it excites an electron, thereby creating a free electron. What is this phenomenon called?

Peltier Effect

Photoelectric Effect

Seebeck Effect

Dipole Effect

The correct answer is Photoelectric Effect. This phenomenon refers to the emission of electrons from a material when it is exposed to light or other electromagnetic radiation. When a photon with sufficient energy strikes the diode, it transfers its energy to an electron, causing it to be excited and break free from the material. This effect is the basis for various applications such as solar cells and photoelectric detectors.

Explanation

The correct answer is Photoelectric Effect. This phenomenon refers to the emission of electrons from a material when it is exposed to light or other electromagnetic radiation. When a photon with sufficient energy strikes the diode, it transfers its energy to an electron, causing it to be excited and break free from the material. This effect is the basis for various applications such as solar cells and photoelectric detectors.

2. By definition, N-type semiconductor has an excess of _______ compared to the P-type region, which has an excess of ______ compared to the N-type region.

Electrons, holes

Holes, electrons

Holes, holes

Electrons, electrons

In a N-type semiconductor, there is an excess of electrons compared to the P-type region, which has an excess of holes compared to the N-type region. This is because in a N-type semiconductor, impurities are added to the crystal lattice, creating extra electrons. On the other hand, in a P-type semiconductor, impurities are added to the crystal lattice, creating extra holes, which are vacancies in the valence band where electrons can move. Therefore, the correct answer is "electrons, holes".

Explanation

In a N-type semiconductor, there is an excess of electrons compared to the P-type region, which has an excess of holes compared to the N-type region. This is because in a N-type semiconductor, impurities are added to the crystal lattice, creating extra electrons. On the other hand, in a P-type semiconductor, impurities are added to the crystal lattice, creating extra holes, which are vacancies in the valence band where electrons can move. Therefore, the correct answer is "electrons, holes".

3. The light consists of small energy packets called _______ according to The Quantum Theory.

Neutron

Krypton

Photon

Proton

The Quantum Theory states that light is made up of small energy packets called photons. Photons are particles that carry electromagnetic radiation and have no mass. They are responsible for transmitting light and other forms of electromagnetic radiation. Neutrons, krypton, and protons are not related to the concept of light consisting of energy packets according to The Quantum Theory.

Explanation

The Quantum Theory states that light is made up of small energy packets called photons. Photons are particles that carry electromagnetic radiation and have no mass. They are responsible for transmitting light and other forms of electromagnetic radiation. Neutrons, krypton, and protons are not related to the concept of light consisting of energy packets according to The Quantum Theory.

4. The presence of dark current decreases the sensitivity of the photodiode to light.

True

False

The presence of dark current in a photodiode refers to the small current that flows through the device even when no light is present. This dark current can limit the sensitivity of the photodiode to detect and measure light accurately. When dark current is present, it adds to the signal being measured, making it more difficult to distinguish between the actual light signal and the noise caused by the dark current. Therefore, the statement that the presence of dark current decreases the sensitivity of the photodiode to light is true.

Explanation

The presence of dark current in a photodiode refers to the small current that flows through the device even when no light is present. This dark current can limit the sensitivity of the photodiode to detect and measure light accurately. When dark current is present, it adds to the signal being measured, making it more difficult to distinguish between the actual light signal and the noise caused by the dark current. Therefore, the statement that the presence of dark current decreases the sensitivity of the photodiode to light is true.

5. Photodiodes operate by absorption of photons or charged particles and generate a flow of current in an external circuit, _______ to the incident power. The light is absorbed __________ with distance and is _________ to the absorption coefficient.

Proportional, exponentially, proportional

Proportional, logarithmically, inversely proportional

Inversely proportional, exponentially, unrelated

Inversely proportional, exponentially, proportional

Photodiodes operate by absorbing photons or charged particles, which leads to the generation of a current in an external circuit. This current flow is directly proportional to the incident power of the light. As the light travels through the photodiode, it is absorbed exponentially with distance, meaning that the absorption decreases rapidly as the distance increases. The absorption coefficient, which represents the probability of absorption per unit distance, is directly proportional to the absorption of light. Therefore, the correct answer is "proportional, exponentially, proportional."

Explanation

Photodiodes operate by absorbing photons or charged particles, which leads to the generation of a current in an external circuit. This current flow is directly proportional to the incident power of the light. As the light travels through the photodiode, it is absorbed exponentially with distance, meaning that the absorption decreases rapidly as the distance increases. The absorption coefficient, which represents the probability of absorption per unit distance, is directly proportional to the absorption of light. Therefore, the correct answer is "proportional, exponentially, proportional."

6. When the p–n junction is forward biased,

The electric charge remains the same as the junction barrier is not affected

The electric charge flow is restricted due to the increased junction barrier

The electric charge flows freely due to the decreased junction barrier

All of these statements are true.

When the p-n junction is forward biased, the electric charge flows freely due to the decreased junction barrier. In a forward biased p-n junction, the positive terminal of the power supply is connected to the p-side and the negative terminal is connected to the n-side. This causes the depletion region to narrow, reducing the junction barrier. As a result, the electric charge carriers (electrons and holes) can easily cross the junction and flow through the circuit. Therefore, the statement that the electric charge flows freely due to the decreased junction barrier is correct.

Explanation

When the p-n junction is forward biased, the electric charge flows freely due to the decreased junction barrier. In a forward biased p-n junction, the positive terminal of the power supply is connected to the p-side and the negative terminal is connected to the n-side. This causes the depletion region to narrow, reducing the junction barrier. As a result, the electric charge carriers (electrons and holes) can easily cross the junction and flow through the circuit. Therefore, the statement that the electric charge flows freely due to the decreased junction barrier is correct.

7. When a diode is reverse biased, the width of the depletion layer __________, causing the capacitance to _________.

Increases, increase

Increases, decrease

Decreases, increase

Decreases, decrease

The boundaries of the depletion region act as the plates of a parallel plate capacitor. The junction capacitance is directly proportional to the diffused area and inversely proportional to the width of the depletion region.

Explanation

The boundaries of the depletion region act as the plates of a parallel plate capacitor. The junction capacitance is directly proportional to the diffused area and inversely proportional to the width of the depletion region.

8. If a diode is reverse biased, the voltage at the anode is higher than at the cathode.

True

False

If a diode is reverse biased, the voltage at the cathode is higher than that at the anode.

Explanation

If a diode is reverse biased, the voltage at the cathode is higher than that at the anode.

9. Dark current is

Produced by forward biasing the photodiode

Produced by the random generation of electrons and holes in the depletion region

Produced by incident photons generating electrons and holes in the depletion region

Produced by reversed biasing the photodiode

Dark current refers to the flow of current in a photodiode even when there is no incident light. This current is produced by the random generation of electrons and holes in the depletion region of the photodiode. These electron-hole pairs are generated due to thermal energy, causing a small current to flow. The dark current can affect the accuracy and sensitivity of the photodiode in low light conditions and needs to be minimized for optimal performance.

Explanation

Dark current refers to the flow of current in a photodiode even when there is no incident light. This current is produced by the random generation of electrons and holes in the depletion region of the photodiode. These electron-hole pairs are generated due to thermal energy, causing a small current to flow. The dark current can affect the accuracy and sensitivity of the photodiode in low light conditions and needs to be minimized for optimal performance.

10. Which can be used as a photo detector in Fiber Optic Communication?

PIN photodiodes

Tunnel diode

LED

LASER diode

PIN photodiodes can be used as a photo detector in Fiber Optic Communication. Unlike tunnel diodes, LED, and LASER diodes, PIN photodiodes have a structure that allows them to efficiently convert light signals into electrical signals. They have a p-type layer, an intrinsic (undoped) layer, and an n-type layer, which creates a large depletion region. This structure enhances the absorption of light, making PIN photodiodes ideal for detecting optical signals in fiber optic communication systems.

Explanation

PIN photodiodes can be used as a photo detector in Fiber Optic Communication. Unlike tunnel diodes, LED, and LASER diodes, PIN photodiodes have a structure that allows them to efficiently convert light signals into electrical signals. They have a p-type layer, an intrinsic (undoped) layer, and an n-type layer, which creates a large depletion region. This structure enhances the absorption of light, making PIN photodiodes ideal for detecting optical signals in fiber optic communication systems.