Find the parameters in a magnetic circuit (ignore the leakage effects)

[Fatima Hasan]

Homework Statement

A coil is uniformly wound on a wooden ring (toroid) as shown in Figure 1. It has 600 turns, and the ring’s cross section area is $1 cm^2$. The total magnetic flux in the ring is 0.2 µWb when the coil carries a current of 800 mA.
When the coil current is raised to 2 A, (assume linear relationship between flux & magnetomotive force ), calculate the followings while ignoring the effects of leakage flux:
a) Flux density in the toroid, B
b) Reluctance of the magnetic flux path, R
c) Mean length of the flux path, lc
d) Magnetic field intensity in the core, Hc
e) Flux linkage of the coil.

Relevant Equations

Equations are attached below.

That was my attempt , but I am not sure if my answer is correct or not .
I want to confirm it .

 

[Babadag]

The magnetic flux density formula is not correct since A=Ac
The reluctance and lc-you have to calculate it in previous conditions when i=800 mA-stay the same.