<span>The correct frequency when you tune a guitar is
when you hear the right tune in your own hearing and standard. The measure
frequency of a guitar string is when you measure the tune of the string
correctly. This is not the same because manual tuning is affected by many
factors.</span>
Answer:

Explanation:
The energy of a single photon is given by:

where
h is the Planck constant
c is the speed of light
is the wavelength
For the photon in this problem,

So, its energy is

One mole of photons contains a number of photons equal to Avogadro number:

So, the total energy of one mole of photons is

It gets attracted due to electro magnetizing
Answer:
B) 100 J
Explanation:
Assuming the distance given is measured along the incline, the vertical change in height is (5 m)(sin 30°) = 2.5 m. Then the change in potential energy is ...
∆PE = mg(∆h) = (4 kg)(10 m/s^2)(2.5 m) = 100 J