Answer:
The wavelength will be 33.9 cm
Explanation:
Given;
frequency of the wave, F = 1200 Hz
Tension on the wire, T = 800 N
wavelength, λ = 39.1 cm

Where;
F is the frequency of the wave
T is tension on the string
μ is mass per unit length of the string
λ is wavelength

when the tension is decreased to 600 N, that is T₂ = 600 N

Therefore, the wavelength will be 33.9 cm
Explanation:
distance = velocity * time
d = 37.9 * 118
distance = 4472.2
Option B & Option D is your correct answers.
'cause here, atom has eight electrons in it's valence shell, so it means it has stable structure which falls in group 18
Hope this helps!