Determine the capacitance of the capacitor.

I just had the most remarkable experience when I read your question ... a formula popped into my head that I haven't used or even thought about in years !  It's the formula for the charge on a capacitor in terms of the voltage across it:

Q = C · V

Charge = (capacitance) · (voltage)

This is exactly what we need in order to answer this question !

For a graph of charge vs voltage (which we have here !), that formula Q=CV is in slope-intercept form, and it says that the capacitance is the slope of the graph.  How awesomely convenient !

The slope of the whole blue line on this graph is

Slope = (0.025 Coulomb) / (50 volts)

Slope = 0.0005

Capacitance = 0.0005 Farad  or  Capacitance = 500 microfarads

answer: the exterior temperature of commercial jet planes as they leave the stratosphere and return to the ground increases steadily.

explanation:

the lower most layer of atmosphere is troposphere which extends from 0 to 12 km above the surface of the earth. the temperature initially decreases as distance is increased from the earth's surface. commercial jets fly in lower part of the stratosphere. the stratosphere extends upto 50 km. the temperature in stratosphere starts rising again due to presence of ozone which traps the uv rays.

thus, when the planes leave the stratosphere and return to the ground, the exterior temperature increases steadily.