☀️ Sources of Energy
Solar Cell – Construction, Working and Applications | Class 10 Science
☀️ Solar Cell – Construction, Working and Applications
1. Introduction | परिचय
A solar cell is a device that converts solar energy directly into electrical energy by the photovoltaic effect.
हिंदी: सौर सेल एक ऐसा उपकरण है जो प्रकाशवोल्टीय प्रभाव (Photovoltaic Effect) के द्वारा सूर्य के प्रकाश की ऊर्जा को सीधे विद्युत ऊर्जा में परिवर्तित करता है।
Solar cells are also called photovoltaic cells or PV cells.
हिंदी: सौर सेल एक ऐसा उपकरण है जो प्रकाशवोल्टीय प्रभाव (Photovoltaic Effect) के द्वारा सूर्य के प्रकाश की ऊर्जा को सीधे विद्युत ऊर्जा में परिवर्तित करता है।
Solar cells are also called photovoltaic cells or PV cells.
Most Important Exam Point: Solar cell converts solar energy directly into electrical energy.
2. What is a Solar Cell?
A solar cell is a semiconductor device that generates an electrical potential difference when light falls on it.
The most commonly used material in conventional solar cells is silicon.
The basic conversion is:
The basic conversion is:
☀️ Solar Radiation → Photovoltaic Effect → ⚡ Electrical Energy
3. Photovoltaic Effect
The photovoltaic effect is the phenomenon in which light falling on a suitable semiconductor creates charge carriers and produces an electrical potential difference.
हिंदी: जब प्रकाश किसी उपयुक्त अर्धचालक पदार्थ पर पड़ता है और उसके कारण विद्युत आवेश वाहक उत्पन्न होकर विभवांतर/विद्युत ऊर्जा प्राप्त होती है, तो इसे प्रकाशवोल्टीय प्रभाव कहते हैं।
हिंदी: जब प्रकाश किसी उपयुक्त अर्धचालक पदार्थ पर पड़ता है और उसके कारण विद्युत आवेश वाहक उत्पन्न होकर विभवांतर/विद्युत ऊर्जा प्राप्त होती है, तो इसे प्रकाशवोल्टीय प्रभाव कहते हैं।
Memory Trick: Photo = Light + Voltaic = Electricity
4. Semiconductor Used in Solar Cell
Silicon is widely used because it is a suitable semiconductor for photovoltaic devices.
A solar cell generally uses a semiconductor structure with a p-n junction.
The p-n junction creates an internal electric field that helps separate photo-generated charge carriers.
The p-n junction creates an internal electric field that helps separate photo-generated charge carriers.
5. Construction of a Solar Cell
A typical silicon solar cell contains:
1. Semiconductor material: Usually silicon.
2. p-type and n-type regions: These form a p-n junction.
3. Front metal contacts: Collect current from the illuminated surface.
4. Back metal contact: Provides the other electrical connection.
5. Anti-reflective coating: Helps reduce reflection and allows more light to enter.
6. Protective glass/encapsulation: Protects the cell from environmental conditions in practical modules.
1. Semiconductor material: Usually silicon.
2. p-type and n-type regions: These form a p-n junction.
3. Front metal contacts: Collect current from the illuminated surface.
4. Back metal contact: Provides the other electrical connection.
5. Anti-reflective coating: Helps reduce reflection and allows more light to enter.
6. Protective glass/encapsulation: Protects the cell from environmental conditions in practical modules.
6. Construction – Animated Diagram
7. Role of P-Type and N-Type Regions
| Region | Important Feature |
|---|---|
| P-type | Contains holes as majority charge carriers. |
| N-type | Contains electrons as majority charge carriers. |
| P-N Junction | Creates an internal electric field that assists separation of photo-generated charge carriers. |
8. Working of a Solar Cell
Step 1 – Light falls on the cell:
Sunlight reaches the semiconductor surface.
Step 2 – Photons transfer energy:
Photons with suitable energy can excite electrons in the semiconductor.
Step 3 – Electron-hole pairs are generated:
Light can create mobile charge carriers.
Step 4 – Charge separation:
The electric field associated with the p-n junction helps separate electrons and holes.
Step 5 – Current flows through the external circuit:
When an external circuit is connected, the separated charges produce an electric current.
Sunlight reaches the semiconductor surface.
Step 2 – Photons transfer energy:
Photons with suitable energy can excite electrons in the semiconductor.
Step 3 – Electron-hole pairs are generated:
Light can create mobile charge carriers.
Step 4 – Charge separation:
The electric field associated with the p-n junction helps separate electrons and holes.
Step 5 – Current flows through the external circuit:
When an external circuit is connected, the separated charges produce an electric current.
Light Energy → Electron-Hole Pairs → Charge Separation → Electric Current
9. Animated Working Diagram
10. Energy Conversion in Solar Cell
Solar Energy → Electrical Energy
The solar cell does not first need to convert sunlight into mechanical energy.
It directly converts light energy into electrical energy through the photovoltaic effect.
11. Solar Cell and Solar Panel
| Solar Cell | Solar Panel / Module |
|---|---|
| Individual photovoltaic unit. | Combination of many interconnected solar cells. |
| Produces relatively small electrical output. | Produces higher useful electrical output. |
| Basic building block of a PV system. | Used for practical electricity generation. |
12. Why Are Many Solar Cells Connected Together?
A single solar cell produces a limited voltage and current.
Therefore, cells are connected in suitable combinations to obtain the required electrical output.
Series connection: increases the total voltage.
Parallel connection: increases the available current.
A group of interconnected cells forms a module/panel.
Series connection: increases the total voltage.
Parallel connection: increases the available current.
A group of interconnected cells forms a module/panel.
13. Series and Parallel Connection
| Connection | Main Effect |
|---|---|
| Series | Voltages add, increasing the overall voltage. |
| Parallel | Currents add, increasing the available current. |
14. Factors Affecting Solar Cell Output
The electrical output of a solar cell/system depends on several factors:
☀️ Intensity of sunlight: Higher irradiance generally increases current output.
📐 Orientation: Proper orientation toward the Sun can increase received radiation.
🌡️ Temperature: Solar-cell electrical characteristics depend on temperature; for common silicon PV cells, higher temperature generally reduces voltage and efficiency.
🧹 Cleanliness: Dust and dirt can reduce the light reaching the cell.
☁️ Weather: Clouds reduce the available solar irradiance.
☀️ Intensity of sunlight: Higher irradiance generally increases current output.
📐 Orientation: Proper orientation toward the Sun can increase received radiation.
🌡️ Temperature: Solar-cell electrical characteristics depend on temperature; for common silicon PV cells, higher temperature generally reduces voltage and efficiency.
🧹 Cleanliness: Dust and dirt can reduce the light reaching the cell.
☁️ Weather: Clouds reduce the available solar irradiance.
15. Advantages of Solar Cells
✔ Renewable source of energy.
✔ No fuel combustion during normal electricity generation.
✔ No moving mechanical parts in a basic PV cell.
✔ Can be installed on rooftops.
✔ Useful in remote locations.
✔ Modular system – capacity can be increased by adding more modules.
✔ Low operating maintenance for many installations.
✔ No fuel combustion during normal electricity generation.
✔ No moving mechanical parts in a basic PV cell.
✔ Can be installed on rooftops.
✔ Useful in remote locations.
✔ Modular system – capacity can be increased by adding more modules.
✔ Low operating maintenance for many installations.
16. Limitations of Solar Cells
❌ Output depends on available sunlight.
❌ Electricity generation falls at night.
❌ Cloudy weather can reduce output.
❌ Initial installation cost can be significant.
❌ Large-scale installations may require considerable land area.
❌ Energy storage or grid backup may be required for supply when sunlight is unavailable.
❌ Electricity generation falls at night.
❌ Cloudy weather can reduce output.
❌ Initial installation cost can be significant.
❌ Large-scale installations may require considerable land area.
❌ Energy storage or grid backup may be required for supply when sunlight is unavailable.
17. Applications of Solar Cells
| Application | Use |
|---|---|
| Solar panels | Electricity generation. |
| Satellites | Power supply in space missions. |
| Calculators | Small electrical power for electronic circuits. |
| Street lights | Solar-powered lighting systems. |
| Rooftop systems | Electricity generation for buildings. |
| Remote communication systems | Power where grid electricity is difficult to access. |
| Water pumping | Electricity for solar-powered pumps. |
| Small electronic devices | Power for suitable low-power applications. |
18. Solar Cell in Space
Solar cells are widely used to provide electrical power to satellites and spacecraft.
The reason is that sunlight is available outside Earth's atmosphere for much of the mission and photovoltaic systems can generate electricity without carrying conventional fuel for the conversion process.
19. Solar Cell vs Solar Cooker
| Solar Cell | Solar Cooker |
|---|---|
| Converts solar energy into electrical energy. | Converts solar energy mainly into thermal energy. |
| Uses photovoltaic effect. | Uses absorption, reflection and heat retention. |
| Uses semiconductor material. | Uses absorber, glass cover, insulation and possibly reflector. |
| Used to generate electricity. | Used for cooking/heating. |
20. Solar Cell vs Solar Panel
| Solar Cell | Solar Panel |
|---|---|
| Single photovoltaic device. | Assembly of multiple interconnected cells. |
| Small output. | Higher practical output. |
| Basic unit. | Practical module used in installations. |
21. Important Terms
| Term | Meaning |
|---|---|
| Photovoltaic Effect | Generation of electrical potential/current due to light interaction with a suitable semiconductor. |
| Photovoltaic Cell | A semiconductor device that converts light into electrical energy. |
| Semiconductor | Material whose electrical conductivity lies between that of conductors and insulators and can be controlled by doping and other conditions. |
| P-Type | Semiconductor region in which holes are majority charge carriers. |
| N-Type | Semiconductor region in which electrons are majority charge carriers. |
| P-N Junction | Boundary between p-type and n-type semiconductor regions. |
| Solar Module | Assembly of interconnected solar cells. |
| Solar Array | Collection of solar modules/panels connected to provide required power. |
22. 30 MCQs | Multiple Choice Questions
1. A solar cell converts solar energy mainly into:
A. Electrical energy
B. Sound energy
C. Chemical energy
D. Nuclear energy
Answer: A
2. The phenomenon responsible for the working of a solar cell is:
A. Electromagnetic induction
B. Photovoltaic effect
C. Heating effect
D. Chemical effect
Answer: B
3. A commonly used semiconductor in solar cells is:
A. Copper
B. Aluminium
C. Silicon
D. Iron
Answer: C
4. A solar cell generally contains a:
A. Transformer
B. Motor
C. Capacitor only
D. P-N junction
Answer: D
5. Majority charge carriers in an N-type semiconductor are:
A. Electrons
B. Holes
C. Protons
D. Neutrons
Answer: A
6. Majority charge carriers in a P-type semiconductor are:
A. Electrons
B. Holes
C. Neutrons
D. Ions only
Answer: B
7. The main function of the P-N junction in a solar cell is associated with:
A. Cooling the cell
B. Producing sound
C. Separating photo-generated charge carriers
D. Blocking all sunlight
Answer: C
8. A solar panel is generally made by connecting:
A. Batteries only
B. Motors
C. Resistors
D. Multiple solar cells
Answer: D
9. Solar cells are particularly useful in satellites because they:
A. Generate electricity from sunlight
B. Burn fuel
C. Produce coal
D. Require wind
Answer: A
10. In a series connection of solar cells, the total voltage generally:
A. Decreases to zero
B. Increases
C. Remains always zero
D. Becomes negative
Answer: B
11. In a parallel connection of solar cells, the available current generally:
A. Increases
B. Becomes zero
C. Always decreases
D. Changes into voltage only
Answer: A
12. Which coating can reduce reflection from the surface of a solar cell?
A. Anti-reflective coating
B. Wood coating
C. Coal coating
D. Rubber coating only
Answer: A
13. Solar cell output generally depends strongly on:
A. Sunlight intensity
B. Sound intensity
C. Soil colour
D. Moonlight only
Answer: A
14. Dust on a solar panel can:
A. Increase sunlight reaching the cells
B. Reduce light reaching the cells
C. Create fuel
D. Increase the Sun's brightness
Answer: B
15. Solar cells are classified as:
A. Photovoltaic devices
B. Heat engines
C. Combustion engines
D. Transformers
Answer: A
16. The basic energy conversion in a solar cell is:
A. Electrical → Solar
B. Solar → Electrical
C. Mechanical → Nuclear
D. Chemical → Solar
Answer: B
17. Which device is an example of photovoltaic technology?
A. Solar cell
B. Solar cooker
C. Gas stove
D. Steam engine
Answer: A
18. Which component provides electrical contact on the back of a typical solar cell?
A. Glass cover
B. Back metal contact
C. Mirror
D. Insulation only
Answer: B
19. The P-N junction is formed by joining:
A. Two metals
B. P-type and N-type semiconductor regions
C. Two insulators
D. Two batteries
Answer: B
20. Which is a limitation of solar cells?
A. They use sunlight
B. They are renewable
C. Output reduces when sunlight is unavailable
D. They can generate electricity
Answer: C
21. Solar cells are useful for:
A. Rooftop electricity generation
B. Producing petrol
C. Producing coal
D. Making rainfall
Answer: A
22. When light creates mobile electrons and holes in a semiconductor, they are called:
A. Photo-generated charge carriers
B. Sound waves
C. Heat engines
D. Magnetic poles
Answer: A
23. A solar module is:
A. A single atom
B. An assembly of interconnected solar cells
C. A fossil fuel
D. A transformer only
Answer: B
24. Which factor can lower the output of a solar panel?
A. Strong sunlight
B. Proper orientation
C. Heavy cloud cover
D. Clean surface
Answer: C
25. Which of the following is not required for the photovoltaic effect itself?
A. Suitable semiconductor
B. Light
C. P-N junction structure in common cells
D. Burning petrol
Answer: D
26. Solar cell technology is considered clean during operation because:
A. It burns coal
B. It burns petrol
C. It does not require fuel combustion during normal generation
D. It produces smoke
Answer: C
27. The electrical output of a PV system can be increased by:
A. Adding suitable modules
B. Covering the cells with dust
C. Blocking sunlight
D. Keeping it permanently in darkness
Answer: A
28. Which material is commonly associated with conventional solar cells?
A. Silicon
B. Wood
C. Plastic only
D. Glass only
Answer: A
29. Solar cells can be used in:
A. Calculators
B. Satellites
C. Rooftop systems
D. All of these
Answer: D
30. The best description of a solar cell is:
A. A device that stores sunlight as fuel
B. A semiconductor device converting light directly into electrical energy
C. A device that converts electricity into sunlight
D. A heat engine using coal
Answer: B
23. Subjective Questions | 2, 3, 4, 5 & 6 Marks
2 Marks
Q1. What is a solar cell?
A solar cell is a semiconductor device that converts solar radiation directly into electrical energy by the photovoltaic effect.
2 Marks
Q2. What is the photovoltaic effect?
It is the phenomenon in which light interacting with a suitable semiconductor produces charge carriers and an electrical potential difference.
2 Marks
Q3. Name a semiconductor commonly used in solar cells.
Silicon is commonly used in conventional solar cells.
2 Marks
Q4. What is the function of the P-N junction?
The P-N junction creates an internal electric field that assists in separating photo-generated charge carriers.
2 Marks
Q5. What is a solar module?
A solar module is an assembly of interconnected solar cells designed to provide useful electrical output.
3 Marks
Q6. Write three advantages of solar cells.
1. Renewable source of energy.
2. No fuel combustion during normal operation.
3. Useful for both grid-connected and remote applications.
2. No fuel combustion during normal operation.
3. Useful for both grid-connected and remote applications.
3 Marks
Q7. Write three limitations of solar cells.
1. Dependence on sunlight.
2. Reduced output during cloudy conditions and at night.
3. Initial installation and storage requirements can be significant.
2. Reduced output during cloudy conditions and at night.
3. Initial installation and storage requirements can be significant.
3 Marks
Q8. Why are many solar cells connected together?
A single cell provides limited voltage and current. Cells are interconnected to obtain the required voltage, current and power output.
3 Marks
Q9. Distinguish between P-type and N-type semiconductors.
P-type semiconductor has holes as majority charge carriers, whereas N-type semiconductor has electrons as majority charge carriers.
3 Marks
Q10. Why is silicon commonly used in solar cells?
Silicon has suitable semiconductor properties and can be manufactured into photovoltaic devices efficiently. It is also relatively abundant and technologically well developed.
4 Marks
Q11. Explain the construction of a solar cell.
A typical solar cell consists of a semiconductor such as silicon with P-type and N-type regions forming a P-N junction. It has front and back electrical contacts. An anti-reflective coating reduces reflection, while protective glass/encapsulation protects practical cells.
4 Marks
Q12. Explain the working of a solar cell.
Sunlight falls on the semiconductor and creates electron-hole pairs. The electric field at the P-N junction helps separate these charges. When an external circuit is connected, charge flows through the circuit, producing electrical current.
4 Marks
Q13. Explain series and parallel connection of solar cells.
In series connection, cell voltages add and the total voltage increases. In parallel connection, currents add and the available current increases. Suitable combinations are used to obtain the required electrical output.
4 Marks
Q14. Mention four applications of solar cells.
Solar cells are used in satellites, calculators, rooftop solar systems and solar-powered street lights. They are also used in remote communication and water-pumping systems.
5 Marks
Q15. Explain the photovoltaic effect in detail.
When light of suitable energy falls on a semiconductor, it can generate electron-hole pairs. The internal electric field associated with the P-N junction helps separate these carriers. This charge separation creates a potential difference. With an external circuit, current flows and electrical energy is obtained.
5 Marks
Q16. Explain the construction and working of a solar cell.
A solar cell generally consists of P-type and N-type semiconductor regions forming a P-N junction, electrical contacts and an anti-reflective/protective surface. Sunlight creates electron-hole pairs. The junction field separates them, and the external circuit allows current to flow, producing electrical power.
5 Marks
Q17. Differentiate between solar cell and solar cooker.
A solar cell converts solar radiation directly into electrical energy through the photovoltaic effect. A solar cooker converts solar radiation mainly into thermal energy using absorption, reflection and heat retention.
5 Marks
Q18. Explain five factors that affect solar-cell output.
Solar irradiance, orientation, temperature, shading/clouds and surface cleanliness affect output. Greater available irradiance generally increases current, while shading and dirt reduce light reaching the cells. Temperature affects the electrical characteristics and efficiency.
6 Marks
Q19. Draw and explain a labelled diagram of a solar cell.
A labelled diagram should show protective glass, anti-reflective coating, front contact, P-type layer, P-N junction, N-type layer and back contact. Light enters from the front, charge carriers are generated and separated at the junction, and current is obtained through the contacts.
6 Marks
Q20. Explain why solar cells are important as a source of energy.
Solar cells use renewable sunlight and directly convert it into electricity without fuel combustion during operation. They can be installed on rooftops, used in remote areas and deployed in large solar power systems. Their modular nature allows systems to be expanded according to requirements.
6 Marks
Q21. Explain the advantages and limitations of solar cells.
Advantages include renewable operation, no fuel combustion during generation, modularity and usefulness in remote areas. Limitations include dependence on sunlight, reduced output during cloudy conditions, no direct generation at night and the possible need for storage or backup.
6 Marks
Q22. Explain the difference between a solar cell, solar module and solar array.
A solar cell is an individual photovoltaic unit. A solar module consists of multiple interconnected solar cells. A solar array consists of multiple modules/panels connected together to provide larger electrical output.
6 Marks
Q23. Explain the role of P-N junction in a solar cell.
The P-N junction establishes an internal electric field. When light creates electron-hole pairs, this field assists in separating the carriers. This separation contributes to the development of a potential difference and allows useful current to flow through an external circuit.
6 Marks
Q24. Explain why solar panels are useful for rooftop electricity generation.
Rooftops provide a location where solar modules can receive sunlight without requiring large additional land areas. The generated electricity can be used locally or, where permitted by the system, supplied to the grid.
6 Marks
Q25. Explain the complete energy conversion process in a photovoltaic system.
Sunlight reaches the photovoltaic cells. Photons interact with the semiconductor and generate charge carriers. The P-N junction helps separate these carriers. Current then flows through the external circuit. An inverter may convert the generated DC electricity into AC for many household or grid applications.
6 Marks
Q26. Why does dust reduce the output of a solar panel?
Dust can block or scatter incoming sunlight before it reaches the photovoltaic surface. Therefore less radiation is available for conversion into electrical energy, reducing output.
6 Marks
Q27. Why is solar energy called a renewable source but solar cells are not an unlimited source of electricity?
Sunlight is renewable, but the electrical output of solar cells is limited by available sunlight, cell efficiency, area, temperature, weather and system capacity. Therefore renewable does not mean unlimited power at every moment.
6 Marks
Q28. Explain the importance of solar cells in remote areas.
Solar cells can generate electricity in places where grid electricity is unavailable or difficult to extend. They can power lights, communication equipment, pumps and other suitable devices, especially when combined with batteries or other storage.
6 Marks
Q29. Explain how a solar panel can be connected to a household system.
Solar modules generate DC electricity. A suitable system may use a charge controller and battery for storage, or an inverter to convert DC to AC for household loads. Grid-connected systems use appropriate protection and metering equipment according to local regulations.
6 Marks
Q30. Write a complete note on Solar Cell – Construction, Working and Applications.
A solar cell is a semiconductor device that converts sunlight directly into electricity through the photovoltaic effect. It commonly contains silicon, P-type and N-type regions, a P-N junction, electrical contacts and protective/anti-reflective layers. Light generates charge carriers and the junction field helps separate them, allowing current to flow through an external circuit. Solar cells are assembled into modules and arrays and are used in satellites, calculators, rooftops, street lighting, water pumping and remote power systems.
24. Assertion–Reason
Assertion (A): A solar cell converts solar energy directly into electrical energy.
Reason (R): A solar cell works on the photovoltaic effect.
Reason (R): A solar cell works on the photovoltaic effect.
Answer: Both A and R are true, and R correctly explains A.
Assertion (A): Silicon is commonly used in solar cells.
Reason (R): Silicon has suitable semiconductor properties for photovoltaic devices.
Reason (R): Silicon has suitable semiconductor properties for photovoltaic devices.
Answer: Both A and R are true, and R correctly explains A.
Assertion (A): Solar cells produce the same output at midnight and noon.
Reason (R): Solar-cell output depends on available solar radiation.
Reason (R): Solar-cell output depends on available solar radiation.
Answer: Assertion is false, but Reason is true.
Assertion (A): Solar panels are made using multiple solar cells.
Reason (R): A single cell generally provides limited electrical output.
Reason (R): A single cell generally provides limited electrical output.
Answer: Both A and R are true, and R correctly explains A.
Assertion (A): Dust on a solar panel can reduce its output.
Reason (R): Dust can reduce the amount of sunlight reaching the photovoltaic surface.
Reason (R): Dust can reduce the amount of sunlight reaching the photovoltaic surface.
Answer: Both A and R are true, and R correctly explains A.
25. HOTS | Higher Order Thinking
HOTS 1: Why are solar cells connected in series and parallel combinations?
Series connections help increase voltage, while parallel connections help increase available current. Appropriate combinations provide the required system output.
HOTS 2: Why does a shaded portion of a solar panel affect its output?
Shading reduces the solar radiation received by the affected cells. Depending on the electrical configuration, the shaded cells can reduce the output of the connected string or module.
HOTS 3: Why can solar cells be used in satellites even though there is no atmosphere like on Earth?
Solar cells do not require atmospheric oxygen or combustion. They convert sunlight directly into electrical energy, making them suitable for spacecraft power systems.
HOTS 4: Why does a solar cell not need a rotating turbine to generate electricity?
A photovoltaic cell converts light directly into electrical energy through the photovoltaic effect. It does not require a mechanical energy conversion stage.
HOTS 5: Why is an inverter often required in a household solar system?
Solar panels generate DC electricity, whereas many household appliances and the utility grid use AC electricity. An inverter converts DC into suitable AC.
26. Golden Points | Exam Revision
☀️ Solar cell = photovoltaic device.
⚡ Main conversion = Solar energy → Electrical energy.
🧪 Common semiconductor = Silicon.
🔗 Basic structure = P-N junction.
➕ P-type majority carriers = Holes.
➖ N-type majority carriers = Electrons.
💡 Light generates electron-hole pairs.
🔌 External circuit allows useful current to flow.
🔋 Many cells together form a module/panel.
🛰️ Important application = Satellites.
🏠 Major application = Rooftop electricity generation.
🌙 No direct sunlight at night → no direct PV generation.
⚡ Main conversion = Solar energy → Electrical energy.
🧪 Common semiconductor = Silicon.
🔗 Basic structure = P-N junction.
➕ P-type majority carriers = Holes.
➖ N-type majority carriers = Electrons.
💡 Light generates electron-hole pairs.
🔌 External circuit allows useful current to flow.
🔋 Many cells together form a module/panel.
🛰️ Important application = Satellites.
🏠 Major application = Rooftop electricity generation.
🌙 No direct sunlight at night → no direct PV generation.
27. One-Minute Revision
☀️ SUNLIGHT
↓ Photons
↓ Semiconductor
↓ Electron-Hole Pairs
↓ P-N Junction
↓ Charge Separation
↓ ⚡ External Current
↓ 🔋 Electrical Energy
↓ Photons
↓ Semiconductor
↓ Electron-Hole Pairs
↓ P-N Junction
↓ Charge Separation
↓ ⚡ External Current
↓ 🔋 Electrical Energy
Memory Trick:
LIGHT → CHARGE → SEPARATE → CURRENT
P = Holes
N = Electrons
PV = Photovoltaic
LIGHT → CHARGE → SEPARATE → CURRENT
P = Holes
N = Electrons
PV = Photovoltaic
28. Concept Map
29. Final Summary
A solar cell is a semiconductor device that converts solar radiation directly into electrical energy through the photovoltaic effect.
A typical solar cell uses silicon and contains P-type and N-type semiconductor regions forming a P-N junction. Electrical contacts collect the generated current, while protective and anti-reflective layers improve practical performance.
When sunlight falls on the semiconductor, it can generate electron-hole pairs. The electric field associated with the P-N junction helps separate these charge carriers. When an external circuit is connected, current flows and electrical energy is obtained.
Many solar cells are connected together to form a solar module/panel, and multiple modules can form a larger solar array.
Solar cells are used in:
✔ Satellites
✔ Calculators
✔ Rooftop solar systems
✔ Solar street lights
✔ Water-pumping systems
✔ Remote communication systems
✔ Large solar power plants
Most Important Exam Line:
☀️ A solar cell converts solar energy directly into electrical energy by the photovoltaic effect.
A typical solar cell uses silicon and contains P-type and N-type semiconductor regions forming a P-N junction. Electrical contacts collect the generated current, while protective and anti-reflective layers improve practical performance.
When sunlight falls on the semiconductor, it can generate electron-hole pairs. The electric field associated with the P-N junction helps separate these charge carriers. When an external circuit is connected, current flows and electrical energy is obtained.
Many solar cells are connected together to form a solar module/panel, and multiple modules can form a larger solar array.
Solar cells are used in:
✔ Satellites
✔ Calculators
✔ Rooftop solar systems
✔ Solar street lights
✔ Water-pumping systems
✔ Remote communication systems
✔ Large solar power plants
Most Important Exam Line:
☀️ A solar cell converts solar energy directly into electrical energy by the photovoltaic effect.
☀️ Class 10 Science | Sources of Energy
Solar Cell • Photovoltaic Effect • P-N Junction • Construction • Working • Applications
CBSE + Foundation + Competitive Preparation
Solar Cell • Photovoltaic Effect • P-N Junction • Construction • Working • Applications
CBSE + Foundation + Competitive Preparation
