Which one of the following pairs of materials serves as electrodes in chargeable batteries commonly used in devices such as torchlights, electric shavers, etc?

The correct pair is nickel and cadmium, which form the electrodes of nickel–cadmium (Ni–Cd) secondary cells — a common rechargeable battery chemistry historically used in portable devices such as torchlights and electric shavers. Text sources list nickel and cadmium among metals found in rechargeable battery systems and note their environmental relevance when discarded [1]. Detailed battery descriptions explain that Ni–Cd cells use nickel oxide/plate as the positive electrode and cadmium as the negative electrode, and classify Ni–Cd as a rechargeable (secondary) battery type used in small devices [3]. Thus nickel and cadmium constitute the electrode pair in the chargeable batteries referenced in the question.

Sources

1. [1] Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 4: Electricity: Magnetic and Heating Effects > A step further > p. 61
2. [2] https://chem.libretexts.org/Courses/City_College_of_San_Francisco/Chemistry_101B/06%3A_Electrochemistry/6.5%3A_Batteries_and_Fuel_Cells
3. [3] https://www.adb.org/sites/default/files/publication/479891/handbook-battery-energy-storage-system.pdf