Galileo Galilei is one of the key figures in the history of Science, being the first to apply the experimental-mathematical scientific method. He carried out experiments and careful observations in kinematics (his studies on the trajectory of projectiles are famous) and dynamics (it should be noted his careful experiments with inclined planes), establishing the first law of Dynamics (which Newton will later collect and refine in his Principles); and in Astronomy, with which he could unequivocally support the heliocentric theory.
His experiments were addressed by methodologies that allowed him to precisely find his mathematical calculations and to verify theories he was developing over time. His manuscripts were key to disseminate the applied method and extrapolate them to other scientific areas.
Therefore the correct answer is C.
Answer:

Explanation:
We need to find the energy for an electron to jump from n = 1 to n = 4.
The energy in transition from 1 state to another is given by :

The difference in energy for n = 1 to n = 4 is:

So, the required energy is equal to
.
To develop this problem it is necessary to apply the concepts related to Wavelength, The relationship between speed, voltage and linear density as well as frequency. By definition the speed as a function of the tension and the linear density is given by

Where,
T = Tension
Linear density
Our data are given by
Tension , T = 70 N
Linear density , 
Amplitude , A = 7 cm = 0.07 m
Period , t = 0.35 s
Replacing our values,



Speed can also be expressed as

Re-arrange to find \lambda

Where,
f = Frequency,
Which is also described in function of the Period as,



Therefore replacing to find 


Therefore the wavelength of the waves created in the string is 3.49m
If this is about simple machines the answer is: Inclined plane