Helium has only 2 electrons in it's valence shell
So, option D is your answer.
Hope this helps!
Answer:
Tension, T = 2038.09 N
Explanation:
Given that,
Frequency of the lowest note on a grand piano, f = 27.5 Hz
Length of the string, l = 2 m
Mass of the string, m = 440 g = 0.44 kg
Length of the vibrating section of the string is, L = 1.75 m
The frequency of the vibrating string in terms of tension is given by :
T = 2038.09 N
So, the tension in the string is 2038.09 N. Hence, this is the required solution.