Correct Option
The correct option isBattery (charging) : Chemical to Electrical
Explanation
Electrical devices operate on the principle of conservation of energy, transforming energy from one form (such as electrical, chemical, or mechanical) into another to perform specific functions.
Option Analysis
- Electric motor : Electrical to Mechanical Electric motor: An electric motor converts electrical energy into mechanical energy. Current flowing through a coil in a magnetic field produces a torque that rotates the motor shaft. This pair is correctly matched.
- Electric iron : Electrical to Heat Electric iron: An electric iron utilizes the heating effect of electric current (Joule heating). It converts electrical energy into heat energy through a high-resistance element. This pair is correctly matched.
- Microphone : Sound to Electrical Microphone: A microphone detects sound waves (mechanical energy) and converts them into corresponding electrical signals. This pair is correctly matched.
- Battery (charging) : Chemical to Electrical Battery (charging): When a secondary battery is being charged, it draws current from an external source. During this process, electrical energy is converted into chemical energy and stored. The conversion of chemical energy to electrical energy occurs during discharging (when the battery is in use). Therefore, this pair is incorrectly matched.
Key Takeaway: In a secondary cell (rechargeable battery), discharging transforms chemical energy into electrical energy, while charging transforms electrical energy back into chemical energy.