Devices often asked

• Simple pendulum, pulleys, levers.
• Hydrometer, pressure cooker, thermos flask.
• Telescope, microscope, periscope.
• Compass, safety fuse, lightning conductor.

How to prepare

• Learn one-line working principle for each device.
• Connect each device to its physics chapter (pressure, heat, optics, electricity).

Common mistake

Memorizing names without principle mapping.
In objective exams, options are often designed to test conceptual mismatch.