Answer:
E=-1.51 eV.

Explanation:
The nth level energy of a hydrogen atom is defined by the formula,

Given in the question, the hydrogen atom is in the 3p state.
Then energy of n=3 state is,

Therefore, energy of the hydrogen atom in the 3p state is -1.51 eV.
Now, the value of L can be calculated as,

For 3p state, l=1

Therefore, the value of L of a hydrogen atom in 3p state is
.
Question
What is the length of the pipe?
Answer:
(a) 0.52m
(b) f2=640 Hz and f3=960 Hz
(c) 352.9 Hz
Explanation:
For an open pipe, the velocity is given by

Making L the subject then

Where f is the frequency, L is the length, n is harmonic number, v is velocity
Substituting 1 for n, 320 Hz for f and 331 m/s for v then

(b)
The next two harmonics is given by
f2=2fi
f3=3fi
f2=3*320=640 Hz
f3=3*320=960 Hz
Alternatively,
and 

(c)
When v=367 m/s then

If you are pushing the coin across the table at a constant rate, the friction of the table and the horizontal force of your hand pushing are equal, and the coin itself moves at a constant rate. If you push a coin and let it go, there is no horizontal force keeping the coin going. Friction slows the coin to a stop. In both cases, the gravitational downward pull of Earth is equally but oppositely resisted by the upward push of table on the coin.
Answer:
I assume the higher notes would make the rice vibrate more easily, so a flute.