Question map
Match List-I with List-II and select the answer using the code given below the Lists : List-I (Device) A. Periscope B. Lightning conductors C. Thermos flask D. Levers List-II (Phenomenon) 1. Conduction and convection minimization 2. Moment of a force 3. Reflection by plane mirrors 4. Static electricity Code : (a) A-2 B-4 C-1 D-3 (b) A-3 B-1 C-4 D-2 (c) A-3 B-4 C-1 D-2 (d) A-2 B-1 C-4 D-3
Explanation
The matching of devices to their physical phenomena is as follows: (A) Periscope utilizes reflection by plane mirrors, typically using two mirrors at 45-degree angles to allow viewing over obstacles. (B) Lightning conductors protect buildings by providing a path for static electricity (lightning) to reach the ground safely, preventing damage from high-voltage atmospheric discharges. (C) A Thermos flask uses a double-wall vacuum design to minimize heat transfer via conduction and convection, thereby maintaining the temperature of its contents. (D) Levers operate on the principle of the moment of a force (torque), where a force applied at one point produces a turning effect around a fixed fulcrum to move a load. This systematic pairing aligns with the principles of geometrical optics, thermal physics, and basic mechanics.