Photons absorbed in matter are coverted to heat. A source emitting n photons/ sec of frequency v 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 increases n, with v fixed
B. decreases with n fixed, v increases
C. remains constant with n and v changing such that nv= const.
D. increases when the product nv increases

Answer

a,b,c

Explanation

Energy spent to convert ice into water `=mL=(1000g)xx(80cal//g)=80000cal`
Energy of photons used`=nTxxE=nTxxhv ( :' E=hv)`
`:. nThv=mL or T=(mL)/(nhv)`
`:. T prop1//n` when v is constant, `T prop1//v` when n fixed, `T prop1//nv`. Thus T is constant if nv is constant. Thus options (a), (b) and (c) are correct.