Explanation:
It is given that,
Fundamental frequency, f = 220 Hz
(a) We know that at 0 degrees, the speed of sound in air is 331 m/s.
For open pipe, 
l is the length of pipe
Also,


(b) Let f' is the fundamental frequency of the pipe at 30 degrees and v' is its speed.


v' = 348.71 m/s
So, 

f' = 232.4 Hz
Hence, this is the required solution.
Answer:
The magnetic flux density is 3 x 10⁵ Wb/m²
Explanation:
Given;
magnetic flux of each line of force, Ф = 30 Wb
area of the bar magnet, A = 1 cm² = 1 x 10⁻⁴ m²
The flux density of the magnet is the measure of the concentration of the magnetic flux per unit area. The unit is Wb/m² or Tesla.
B = Ф / A
B = 30 / (1 x 10⁻⁴ )
B = 3 x 10⁵ Wb/m²
Therefore, the magnetic flux density is 3 x 10⁵ Wb/m²