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Rechargeable Batteries
- Rechargeable batteries can be charged and used many times.
- This prevents wastage and saves money.
- They are used in watches, phones, laptops, and vehicles.
- But they do not last forever and slowly wear out.
Example 1 — Phone Battery
- A phone battery runs down after use.
- It is charged again from a socket.
- So the same battery is used many times.
Example 2 — Old Battery
- A battery is charged and used for a year or two.
- It now needs charging more often.
- So it has slowly worn out.
Important Points
- Rechargeable batteries range from tiny watch cells to big vehicle batteries.
- They wear out after being charged and used many times.
Definition — Rechargeable Battery
A rechargeable battery is a battery that can be charged and reused many times before it wears out.
⭐ A Step Further — Li-ion and Future Batteries
The lithium-ion battery is the most common rechargeable battery today. It uses metals like lithium and cobalt, found in limited parts of the world.
Scientists are now working on solid-state batteries. These would be safer, charge faster, and last longer. Better batteries help the world move to clean power.
♻️ A Step Further — Recycle Old Batteries
Even a dead battery is not fully empty. It still has acids and metals like lead, cadmium, nickel, or lithium.
Thrown in normal garbage, these can cause fires or harm the environment. So take old batteries to an e-waste recycling point. Recycling is good for the planet and people.
🧠 Test Yourself — Section 4.3
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How does a cell make electricity?
View Answer
From chemical reactions taking place inside it. -
What is the electrolyte in a lemon cell?
View Answer
The lemon juice, which helps conduct electricity. -
Why is a dry cell called dry?
View Answer
Because its electrolyte is a moist paste, not a liquid. -
When is a cell called dead?
View Answer
When its chemicals are used up and it cannot make current. -
Why should we recycle old batteries?
View Answer
They have acids and metals that can harm the environment, and their materials can be reused.
📋 NCERT Question 1 — Fill in the blanks
The solution used in a Voltaic cell is called ____. A current carrying coil behaves like a ____.
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📋 NCERT Question 9 — Which LED will glow
In Fig. 4.11, one beaker has lemon juice and one has pure water, each with copper and iron. In which case will the LED glow?
View Answer →
