Passage VII
Ferromagnetic materials become magnetic when they are placed in an external magnetic field.
Figures 1 and 2 are graphs of the total magnetic field, B, versus the intensity of the external magnetic field, H, for Materials X and Y, respectively. (B = µ0 [M + H], where µ0 is a constant and M is the magnetization of the material.) B varies as H is increased from zero, then decreased, then increased again, as shown by the directions of the arrows in the figures. If B is not zero when H returns to zero, a material has been magnetized.
When B or H is positive(negative), it is described as pointing north(south).
40. Consider the most positive value of B and the most negative value of B on the graph in Figure 1. How are these two values of B related? The most negative value of B is equal to:
Your Answer is
Correct Answer is F
Explanation
Look at figure 1, the graph is symmetrical about the X axis, and the maximum and minimum values are only the difference between positive and negative. So, (-B)×(-1)=+B