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:

Explanation:
Acceleration is defined as the change in velocity divided by the time it took to produce such change. The formula then reads:

Where Vf is the final velocity of the object, (in our case 80 m/s)
Vi is the initial velocity of the object (in our case 0 m/s because the object was at rest)
and t is the time it took to change from the Vi to the Vf (in our case 0.05 seconds.
Therefore we have:

Notice that the units of acceleration in the SI system are
(meters divided square seconds)
You need to use Planck's law:
E = h·υ = (h·c)/λ
Without making all the calculations, a fraction is bigger than another when the denominator is smaller. Therefore you need to find the smallest wavelength (λ) which is 450nm.
You could also be helped by colors: in order of decreasing energy, you have blue - green - yellow - red.
In any case, the correct answer is a).
I’m not really sure but I think it’s D type 1 lever
Las ciencias naturales usan y obedecen los principios y leyes establecidos por el campo. ... El campo de la física es extremadamente amplio y puede incluir estudios tan diversos como la mecánica cuántica y la física teórica, la física aplicada y la óptica.