De Broglie's identity gives the relationship between the momentum and the wavelength of a particle:

where
p is the particle momentum
m is its mass
v its velocity
h is the Planck constant

is the wavelength
By re-arranging the equation, we get

and by using the data about the proton, given in the text, we can find the proton's wavelength:
it is also known as formula for circumfrence which is 2 times pi times radius. if radius was 5 then the circumfrence would be 10pi.
Answer c, velocity would be the answer.
Answer:
5773.50269 Hz
23 A
Explanation:
= Inductance = 6 mH
= Capacitance = 5 μF
= Resistance = 3 Ω
= Maximum emf = 69 V
Resonant angular frequency is given by

The resonant angular frequency is 5773.50269 Hz
Current is given by

The current amplitude at the resonant angular frequency is 23 A