Identify the incorrect statement.(A) Power meters work on the princip…

The correct answer is Option (4) → (D) only

Eddy currents are currents induced in bulk pieces of conductor by a changing magnetic flux. A statement is marked Incorrect below if it is false as a statement of physics.

(A) Power meters work on the principle of Eddy currents. — Correct. The metal disc of an analogue electric power meter is turned by eddy currents induced in it by the varying magnetic fields of a coil.

(B) Induction furnace uses eddy currents to produce heat. — Correct. A high-frequency current in a coil induces eddy currents in the metal inside it, and these heat it enough to melt it.

(C) Eddy currents can be used to produce braking force in moving trains. — Correct. Eddy currents induced in the rails by electromagnets oppose the motion (Lenz's law) and give smooth braking.

(D) Eddy currents are produced in a steady magnetic field. — Incorrect. Induction needs a change of flux. In a steady field, with no relative motion, there is no flux change and no eddy current.

Note: This question is from the pre-rationalised NCERT book (2022-23). The topic was removed from the latest NCERT book (2026-27), and it also appears to be out of the CUET 2026 syllabus.

NCERT (Pre-rationalised edition, 2022-23):
Eddy Currents – “… Even when bulk pieces of conductors are subjected to changing magnetic flux, induced currents are produced in them.”

Eddy Currents – “… (i) Magnetic braking in trains: Strong electromagnets are situated above the rails in some electrically powered trains.”

Eddy Currents – “… (iii) Induction furnace: Induction furnace can be used to produce high temperatures and can be utilised to prepare alloys, by melting the constituent metals.”

Eddy Currents – “… (iv) Electric power meters: The shiny metal disc in the electric power meter (analogue type) rotates due to the eddy currents.”