Match List I with List II.LIST I (Devices)LIST II (Principles)A.Poten…

The correct answer is Option (2) → A-II, B-IV, C-III, D-I

Each device is matched with the physical principle on which it works.

(A) Potentiometer — this matches (II) Potential Gradient. A steady current through a uniform wire gives a constant potential drop per unit length, so an unknown emf is measured by its balancing length.

(B) Moving coil galvanometer — this matches (IV) Radial Magnetic field. The concave pole pieces and soft iron core make the field radial, so the deflection is proportional to the current.

(C) Transformer — this matches (III) Mutual Induction. The changing current in the primary changes the flux linked with the secondary and induces an emf in it.

(D) Meter bridge — this matches (I) Wheatstone Bridge. It is a practical Wheatstone bridge, balanced when \( P/Q = R/S \).

Note: Items (B), (C) and (D) of this question are from the latest textbook (2026-27). Item (A), that the potentiometer works on the potential gradient, is printed only in the pre-rationalised textbook (2022-23). It was removed from the latest book, and it also appears to be out of the CUET 2026 syllabus.

NCERT (2026-27):
The Moving Coil Galvanometer – “… The galvanometer consists of a coil, with many turns, free to rotate about a fixed axis (Fig. 4.20), in a uniform radial magnetic field.”

Transformers – “… This is done with a device called transformer using the principle of mutual induction.”

Wheatstone Bridge – “… The bridge then is balanced, and from the balance condition the value of the unknown resistance R₄ is given by,

    \( \displaystyle R_4 = R_3 \frac{R_2}{R_1} \qquad [3.64(b)] \)

A practical device using this principle is called the meter bridge.”

NCERT (Pre-rationalised edition, 2022-23):
Potentiometer – “… Since the wire is uniform, the potential difference between A and any point at a distance l from A is

    \( \displaystyle \varepsilon(l) = \phi\,l \qquad (3.89) \)

where φ is the potential drop per unit length.”