Answer:
Explanation:
Given
Lowest four resonance frequencies are given with magnitude
50,100,150 and 200 Hz
The frequency of vibrating string is given by

where n=1,2,3 or ...n
L=Length of string
T=Tension
Mass per unit length
When string is clamped at mid-point
Effecting length becomes 
Thus new Frequency becomes

i.e. New frequency is double of old
so new lowest four resonant frequencies are 100,200,300 and 400 Hz
Answer:
Wavelenght is 4.53x10^-7m
Explanation:
Detailed explanation and calculation is shown in the image below
The electrical force between these two charges remains the
same. In coulomb’s law, it states that the magnitude of two charges (product of
two charges) is inversely proportional to the square of the distance. Since both
the magnitude and the distance are halved, therefore, the change in both quantities
will have no effect in the value of electrical force.