Photons absorbed in matter are converted to heat. A source emitting n photons/ sec of frequency `nu` is used to convert 1kg of ice at `0^(@)C` to water at `0^(@)C`. Then, the time T taken for the conversion

Options

A. decreases with increasing n, with v fixed.
B. decreases with n fixed, v increasing.
C. remains constant with n and v changing such that nv=constant.
D. All of these.

Answer

D

Explanation

(d) : Energy spent to convert ice into water `=mL=(1000g)xx80calg^(-1)=80000cal`
Energy of photons used `=nTxxE=nTxxhv`
`:.nThv=mL or T=(mL)/(mhv)`
`:.Tprop1//n"when v is constant",Tprop1//v"when n fixed",Tprop1//nv."Thus T is constant if is constant. Thus options (a), (b) and (c) are correct"`.