A long straight solenoid has 800 turns. When the current in the solenoid is 2.90 amperes the average flux through each turn is 3.25×10−3Wb. A. What is the inductance of the coil?
B. What must be the magnitude fo the rate of change of the current (di/dt) in order for the self-induced emf to equal 7.50 mV?

Explanation:

Relation between flux and inductance is as follows

φ = Li

where φ is flux associated with induction of inductance L when a current i flows through it

putting the values

3.25 x 10⁻³ x 800 = L x 2.9

L = .9 H

for induced emf in an induction , the relation is

emf induced = L di / dt

Putting the values

7.5 x 10⁻³ = .9 x di / dt

di / dt = 8.33 x 10⁻³ A / s

e) none of the above answers are correct

answer;

d. are made mostly of liquid

explanation;

-the general   composition and structure planets includes; they have a thick gas and liquid layer covering a small,solid core. mostly the gases are hydrogen and helium atmosphere and layers of liquid hydrogen. for instance neptune and uranus are examples of the outer planets, they have a core covered by ice and ammonia.

-neptune's atmosphere is hydrogen and helium with a bit of methane so there is no oxygen to breath and the interior is made up of frozen water and ammonia with a rock and iron core. thus, there is no liquid water or solid surface to survive.