Arefrigeration cycle operating between two reservoirs receives energy qc from a cold reservoir at tc = 275 k and rejects energy qh to a hot reservoir at th = 315 k. for each of the following cases, determine whether the cycle operates reversibly, operates irreversibly, or is impossible: (a) qc = 100 kj, wcycle = 80 kj. (b) qc = 1200 kj, qh = 2000 kj. (c) qh = 1575 kj, wcycle = 100 kj. (d) β = 8.

you'd use the equation that establishes a relationship between  energy  and  wavelength, which looks like this

e=h⋅cλ, where

λ  - the wavelength of the photon; c  - the speed of light, usually given as  3⋅108m/s; h  -  planck's constant, equal to  6.626⋅10−34j s

plug the value you were given for the energy of the photon in the above equation to get the wavelength

e=h⋅cλ⇒λ=h⋅ce

λ=6.626⋅10−34js⋅3⋅108ms−1.257⋅10−24j=1.581⋅10−1m