[amp_mcq option1=”The entire bulk of the bar gets magnetised” option2=”Only the surface of the bar gets magnetised” option3=”Only the ends of the bar get magnetised” option4=”Only some parts of the outer layers of the bar get magnetised” correct=”option1″]
The correct answer is: A. The entire bulk of the bar gets magnetised.
When a bar of iron is magnetized, the electrons in the atoms of the iron align themselves in the same direction. This creates a magnetic field around the bar. The magnetic field is strongest at the ends of the bar, and it weakens as you move away from the ends. However, the entire bulk of the bar is magnetized, not just the surface or the ends.
Option B is incorrect because only the surface of the bar would be magnetized if the magnetic field were only present on the surface. Option C is incorrect because only the ends of the bar would be magnetized if the magnetic field were only present at the ends. Option D is incorrect because only some parts of the outer layers of the bar would be magnetized if the magnetic field were only present in the outer layers.