The energy of a photo having a wavelength of 10^{-10}m is

(h= 6.63 x 10 ^{-34}Js, c =3.0 x 10 ^{8}ms^{-1})

Answer Details

The energy of a photon can be calculated using the formula:
Energy = Planck's constant × frequency
where frequency = speed of light / wavelength.
In this question, the wavelength of the photon is given as 10^-10 m, and the values of Planck's constant (h) and the speed of light (c) are also given.
So, we can calculate the frequency of the photon as:
frequency = c / wavelength
= (3.0 x 10^8 m/s) / (10^-10 m)
= 3.0 x 10^18 Hz
Now, we can use the above formula to calculate the energy of the photon as:
Energy = h × frequency
= (6.63 x 10^-34 J s) × (3.0 x 10^18 Hz)
= 1.89 x 10^-15 J
Therefore, the energy of the photon is 1.89 x 10^-15 J, which is closest to option A: 2.0 x 10^-15 J.