Two aluminized optical flats 15 cm in diameter are separated by a gap of 0.04 mm, forming a capacitor. what is the capacitance in picofarads

3978 pF

Explanation:

Capacitance can be defined as ability to store charge. It is the ratio of charge  over electric potential.

where, A is the area of the plates and d is the distance between plates forming the capacitor.

diameter of the plates, di = 15 cm =0.15 m

radius of the plate, r = di/2 = 0.075 m

Area of the plates, A = πr² = 0.018 m²

Distance between the plates, d = 0.04 mm = 0.00004 m

Permittivity, ∈₀ = 8.84 × 10⁻¹² F/m

Capacitance,

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.