‘Dynamo’ is a device, which converts

The correct answer is C. A dynamo is a generator of direct current. It works on Faraday's law of electromagnetic induction: when a coil rotates in a magnetic field, the flux linkage changes and an emf is induced. The mechanical input (a hand crank, a belt from an engine, a turbine) is converted into electrical output. A commutator keeps the output unidirectional, which distinguishes a DC dynamo from an alternator, though both convert mechanical energy into electrical energy.

Why the others are wrong:

• A: Chemical-to-electrical conversion is the job of a cell or battery, where electrode reactions drive current.
• B: Electrical-to-mechanical conversion is a motor. It uses the same electromagnetic principle with the roles reversed, governed by Fleming's left-hand rule.
• D: Electrical-to-chemical conversion happens in electrolysis, electroplating or battery charging. A dynamo does not do this.

Core concept: energy conversion devices and electromagnetic induction. Mains link: thermal, hydro and wind power generation all rely on this principle, so it connects to questions on energy infrastructure and energy security.

Trap: candidates pick B because they remember the dynamo and motor together and mix up the direction. Ask which way the energy flows inside the device itself.