Which one of the following statements is not correct?

Statement 2 is incorrect because magnetic field lines are most concentrated, not widely separated, near the poles of a magnet. The density of field lines represents the strength of the magnetic field; since the field is strongest at the poles, the lines are closest together there [3]. Statement 1 is correct as the Earth's magnetic field originates from the geodynamo effect, caused by the motion of molten iron and nickel in the outer core [2]. Statement 3 is correct based on the definition of magnetic flux density (B = Φ/A); if the area (A) increases while flux (Φ) remains constant, the density (B) must decrease. Statement 4 is correct according to Faraday's Law of Induction and the concept of motional EMF, where the induced voltage is proportional to the velocity of the conductor moving through the magnetic field [4].

Sources

1. [3] Science , class X (NCERT 2025 ed.) > Chapter 12: Magnetic Effects of Electric Current > What you have learnt > p. 206
2. [1] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 5: Earths Magnetic Field (Geomagnetic Field) > 5.4. Dynamo Theory: Generation of Earth's Magnetic Field and Sustaining it > p. 71
3. [2] Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 13: Our Home: Earth, a Unique Life Sustaining Planet > 13.3.3 Magnetic field of the Earth > p. 217
4. [4] Science , class X (NCERT 2025 ed.) > Chapter 12: Magnetic Effects of Electric Current > EXERCISES > p. 207