Current set NDA-II · 2016 Q81

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Q81 (NDA-II/2016) Science & Technology › Basic Science (Physics, Chemistry, Biology) › Electricity and magnetism Answer Verified

Which one of the following statements is not correct ?

A

The SI unit of charge is ampcre- second

B

Debye is the unit of dipole moment

C

Resistivity of a wire of length / and area of cross-section a depends upon both / and a

D

The kinetic energy of an electron of mass m kg and charge e coulomb, when accelerated through a poten¬tial difference of V volt, is eFjoulc

Result

Your answer: — · Correct: C

Explanation

Statement 3 is incorrect because resistivity (ρ) is an intrinsic property of a material and does not depend on the physical dimensions of the conductor, such as its length (l) or area of cross-section (A) [2]. While the resistance (R) of a wire is directly proportional to its length and inversely proportional to its cross-sectional area (R = ρl/A), the resistivity remains constant for a given material at a specific temperature [2]. Regarding the other options: the SI unit of charge is the Coulomb, which is equivalent to an ampere-second (I = Q/t, so Q = It). Debye is a standard non-SI unit for electric dipole moment. Finally, the kinetic energy gained by an electron accelerated through a potential difference V is indeed eV joules, as work done (W) equals charge (e) multiplied by potential difference (V) [3].

Sources

[1] Science , class X (NCERT 2025 ed.) > Chapter 11: Electricity > What you have learnt > p. 192
[2] Science , class X (NCERT 2025 ed.) > Chapter 11: Electricity > Activity 11.3 > p. 178
[3] Science , class X (NCERT 2025 ed.) > Chapter 11: Electricity > 11.2 ELECTRIC POTENTIAL AND POTENTIAL DIFFERENCE > p. 173

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Which one of the following statements is not correct ?

Explanation

SIMILAR QUESTIONS

A positive charge +q is placed at the centre of a hollow metallic sphere of inner radius a and outer radius b. The electric field at a distance r from the centre is denoted by E. In this regard, which one of the following statements is correct ?

Which one of the following correctly represents the SI unit of resistivity?

For a material under static conditions, which one among the following statements is correct ?