Aparallel-plate capacitor has a voltage of 391 v applied across its plates, then the voltage source is removed. what is the voltage across its plates if the space between them becomes filled with mica? (the dielectric constant for mica is 5.4 and for air is 1.0006.)

When the capacitor is connected to the voltage, a charge Q is stored on its plates. Calling the capacitance of the capacitor in air, the charge Q, the capacitance and the voltage () are related by

(1)

when the source is disconnected the charge Q remains on the capacitor.

When the space between the plates is filled with mica, the capacitance of the capacitor increases by a factor 5.4 (the permittivity of the mica compared to that of the air):

this is the new capacitance. Since the charge Q on the plates remains the same, by using eq. (1) we can find the new voltage across the capacitor:

And since , substituting into the previous equation, we find:

not too sure thinking it will always be directed towards the centre of the earth. could be wrong not sure

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.