Answer: 0.1 m, 0.0583 m
Explanation:
We are given that:
Frequency for throat= 800 Hz
Frequency for mouth= 1500 Hz
Sound speed= 350 m/s
We have to find the corresponding lengths.
We have
f= 
or L=
For the throat= L=
= 0.1 m
For the mouth= L=
= 0.0583 m
Substract two consecutive terms of the sequence to see if there is a common difference:

As we can see, there is a common difference of -6.
Then, if a number of the sequence is given, the next one can be found by adding -6 (which is the same as subtracting 6).
Notice that the first term of the sequence is 3.
Then, the rule for the sequence is to start with 3 and add -6 repeatedly.
Therefore, the correct choice is option A) Start with 3 and add -6 repeatedly.
Answer:
Number of turns per unit length will be 
Explanation:
We have given that strength of the magnetic field produced by the solenoid B = 7 T
Current in the solenoid i = 200 A
Let the number of turns per unit length is n
Magnetic field due to solenoid is given as
here
is permeability of free space n is number of turns per unit length and i is current
So 
