Why do photographs in a book or magazine look grainy when magnified?

Q: A cavity radiator has its maximum spectral radiance at a wavelength of 6,9×10-7 m. If the body is…

A:

Q: A photon of red light having wavelength 660 nm has energy equal to (h= 6.6 × 10-34Js) A 1.0 × 10-¹⁹J

A: Given data, Wavelength of photon λ=600 nm=600×10-9 m. Plank's constant h=6.6×10-34 J-s.

Wien's displacement law

Students often get confused between Wien's displacement law and Planck's radiation law. Although both are historically related, yet they are conceptually different. Planck's law helps determine the spectrum of a blackbody, while Wien's law determines the relationship between peak wavelength and temperature.