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 5
 Homework Statement

A blacksmith puts an iron rod in a furnace and takes it out when it starts glowing red. Assume the wavelength of the red light emitted by the rod to be 700 nm. The temperature of the rod should be (Wien’s constant = 2.898 x 103 m.K):
(a) 4140 K
(b) <4140 K
(c) >4140 K
(d) In the range 4140 K4240 K
 Homework Equations
 Wien's Displacement Law λT=2.898*10^3
Given λ=700nm, we use the equation mentioned above and find the Temperature to be 4140K. However, my doubt is that the wavelength specified to be used above is a maximum and I'm not sure if the answer is (a) or (d) considering that the latter is a range of the temperature.