Passage VII

In the ionosphere (the atmosphere between 50 km and 2,000 km above Earth's surface), gaseous atoms and molecules lose electrons and become ions when struck by energetic solar radiation (X-rays and ultraviolet radiation). The figure shows the electron density, in free electrons/cm3, for a portion of the ionosphere above a 45°N latitude location. The electron density and the specific ions present in the D, E, and F layers of the ionosphere are important in the long-distance transmission of high frequency radio signals. Electron density varies between daytime and nighttime as well as between maximum sunspot count and minimum sunspot count.

37. Which of the following graphs best represents the nighttime and the daytime electron densities shown in the figure for an altitude of 200 km at minimum sunspot count?

Answer and Explanation

Your Answer is

Correct Answer is B

Explanation

The condition in the question stem is minimum sunspot count, so you should look at the two dotted lines in the picture, and then look at the altitude given in the question is 200 km, so when the ordinate is 200, the abscissa corresponding to the daytime curve is about It is 105, and the abscissa of nighttime is about 103, so you should choose B