WhG exactly are you asking question mark
Answer:
1184 kJ/kg
Explanation:
Given:
water pressure P= 28 bar
internal energy U= 988 kJ/kg
specific volume of water v= 0.121×10^-2 m^3/kg
Now from steam table at 28 bar pressure we can write


therefore at saturated liquid we have specific enthalpy at 55 bar pressure.
that the specific enthalpy h = h at 50 bar +(55-50)/(60-50)*( h at 50 bar - h at 60 bar)

h= 1184 kJ/kg
The correct answer to your question and how to solve it is
The relation between wavelength (λ)and the frequency of electromagnetic oscillation (f) is described by the following expression: λ=c/f, where c–is the speed of light in vacuum = 3*10^8 m/s
Derive f from above: f = c/λ.How to Calculate: λ=890nm = 890*10^-9m = 8.9*10^-7m
f =3*10^8m/s Divided by 8.9*10^-7m = 0.34*10^15 s-1=3.4*10^14 s-1
So your Answer is: The frequency of radiation of wavelength 890 nm is 3.4*10^14s-1
I think that chalk is a compound. it is made up of molecules containing one calcium atom ,one carbon atom and three oxygen atoms.