📖 Chapter 3 of 8 · Green Energy - Basic 2 · Class 7
Chapter 3: How Does a Solar Panel Make Electricity?
In this chapter
- What is inside a solar panel?
- How sunlight turns into electric current — step by step.
- Solar power on rooftops, in villages and in study lamps.
- Meet Hetal from Gujarat and Jonali from Assam.
The Big Idea
A solar panel is made of many small solar cells. Each cell has a thin layer of silicon, which is made from very pure sand. When sunlight falls on the silicon, it gives tiny particles called electrons a push. The moving electrons flow through wires — and that flow is electricity! A solar panel has no moving parts, makes no noise and gives no smoke.
Did You Know?
Scientists call solar cells photovoltaic cells. “Photo” means light and “voltaic” means electricity — so the name simply means “light-electricity”!
Story Time — Hetal’s Village Runs on Sunshine
Hetal, age 10 · Modhera, Mehsana district, Gujarat
Hetal lives in Modhera, a village in Gujarat known for its beautiful Sun Temple, built almost a thousand years ago. Her Ba (grandmother) loves telling her, “Our ancestors prayed to Surya Dev. Now the Sun also runs our fridge!”
In 2022, Modhera became known as India’s first solar-powered village. Blue panels now sit on the roofs of the houses, and a large solar plant with batteries was built nearby, so homes can have power even after sunset.
One afternoon, an engineer didi came to check the panels on Hetal’s roof. Hetal climbed up behind her. “Didi, how does a flat blue sheet make electricity? Nothing is moving!”
Didi smiled and tapped a panel. “Inside are many cells made of silicon. When sunlight hits them, tiny electrons get a push and start moving. Wires carry them to a box called an inverter, which changes the power into the kind our fans and TV use.”
“And when our roof makes more power than we need?” Hetal asked. “The extra goes into the village lines for others to use, and your family’s bill becomes much smaller,” said Didi. Ba clapped her hands. “Surya Dev is now paying our bills too!”
Story Time — Jonali’s Light on the River Island
Jonali, age 11 · Majuli, Assam
Jonali lives on Majuli, a large river island in the mighty Brahmaputra. Her family’s house stands on wooden stilts called a chang ghar, so that flood water can flow underneath during the monsoon.
When heavy rains came, the electricity often went off for many nights. Jonali used to study by a small kerosene lamp. Its smoke made her eyes sting, the room smelled bad, and Maa always worried about fire.
Last year, Jonali’s school gave every student a solar study lamp. It has a tiny panel that sits in the sunny courtyard all day. The panel charges a small battery inside the lamp. At night, Jonali presses a button and a bright white LED glows for hours.
“No smoke, no smell and no money spent on kerosene!” said her father happily. Even her little cousins now come over to read picture books in the lamp’s clean light.
Jonali finished her exams with her best marks ever. She wrote in her diary: “The Sun shines on me twice — once in the day, and once again at night through my lamp.”
How Does a Solar Cell Work?
Follow the numbers in the picture to see sunlight turn into electricity.
- 1. Light hits the cell. Sunlight carries energy in tiny packets.
- 2. Electrons jump. The light gives electrons in the silicon a push, and they start to move.
- 3. They flow in wires. Metal lines on the cell collect the moving electrons and send them into a wire. A flow of electrons is called an electric current.
- 4. The bulb glows. The current passes through the bulb and lights it up, then returns to the cell to go round again.
- Words to know: many cells make a panel; many panels make an array; an inverter changes panel power into the kind used at home.
India on the rooftops: In 2024, the Government of India started the PM Surya Ghar Muft Bijli Yojana to help one crore families put solar panels on their roofs.
Solved Examples
Think first, then read the answer.
1. What is a solar cell made of?
Show answer
Answer: Mainly silicon, a material made from very pure sand, with thin metal lines on top and a metal layer underneath to carry the current.
2. Why does a solar panel give less power on a cloudy day?
Show answer
Answer: Clouds block some of the sunlight. Less light means fewer electrons get a push, so less electricity flows.
3. Does a solar panel work at night?
Show answer
Answer: No, because there is no sunlight. To use solar power at night, we store it in batteries during the day (see Chapter 6).
4. In India, which direction should rooftop solar panels face, and why?
Show answer
Answer: Mostly towards the south, tilted a little. India is north of the equator, so the Sun moves across the southern part of our sky.
5. A rooftop system makes 4 units a day. A family uses 150 units a month. How many units must come from the power lines in a 30-day month?
Show answer
Answer: Solar in 30 days = 4 × 30 = 120 units. From the lines = 150 − 120 = 30 units.
✎ Now You Try!
A solar lamp charges for 6 hours in the day and glows for 4 hours at night. Which time is longer, and by how many hours?
Check Your Understanding
A. Fill in the blanks
- A solar panel is made of many small solar .
- Solar cells are made mainly of , which comes from pure sand.
- A flow of electrons is called an electric .
- Modhera in is known as India’s first solar-powered village.
- Jonali’s house on Majuli stands on wooden .
B. True or False
- A solar panel has many moving parts. ( ___ )
- Solar panels make more power on sunny days. ( ___ )
- A solar lamp stores energy in a battery for the night. ( ___ )
- An inverter changes panel power into the kind used at home. ( ___ )
C. Choose the correct option
- Photovoltaic means (a) light-electricity (b) wind-power (c) water-wheel
- Rooftop panels in India mostly face (a) north (b) south (c) the ground
- Before the solar lamp, Jonali used a (a) kerosene lamp (b) torch (c) candle only
D. Answer in two or three sentences
- Explain in four steps how a solar cell makes electricity.
- Give two reasons why the solar lamp was better than the kerosene lamp.
- What happens to the extra power made on Hetal’s roof?
Brain Buster
Stand in the sunshine and then in the shade. Where would a solar panel work better, and why?
Check your understanding
Tap an answer to see if it is correct. This is just for fun — nothing is saved.
1. What are solar cells mainly made of?
- Silicon, made from pure sand
- Plastic
- Copper coins
Show answer
A. Silicon, made from pure sand
2. What does the light do inside a solar cell?
- It melts the cell
- It gives tiny electrons a push so they flow
- It makes the cell spin
Show answer
B. It gives tiny electrons a push so they flow
3. Which direction should rooftop panels in India mostly face?
- North
- South
- Straight down
Show answer
B. South
4. Why was Jonali’s solar lamp better than her kerosene lamp?
- It made more smoke
- No smoke, no smell and no fuel cost
- It needed petrol
Show answer
B. No smoke, no smell and no fuel cost