A guitar string 66 cm long vibrates with a standing wave that has two antinodes.
1.Which harmonic is this
2.what is the wavelength

This is in the 2nd harmonic

The wavelength of the harmonic is λ=66

Explanation:

Given data

length= 66cm  antinodes= 2

1.To find the harmonic

We have the formula,

No of antinodes= No of harmonic

2=2

This is in the 2nd harmonic

2.The wavelength of the harmonic

We have the formula,

λ=2L/n=2 66/2

λ=66

The wavelength of the harmonic is λ=66

b.

explanation:

10.0

electrical potential energy =0.072 j

explanation:

electrical potential energy is given by

u= q δv

q= charge=6 c

δv= potential difference and is given by

δv= e d

e= electric field

d= distance=5 mm=0.005 m

δv=2.4 (0.005)=0.012 v

now electric potential energy= u= q δv

u=6 (0.012)

u=0.072 j