I need a fan!

Classical Mechanics Level 3

A 50-watt immersion heater just keeps 375 g 375\text{ g} of a molten material at its melting point. If I switch off the heater, then the temperature starts falling 5 minutes later. Calculate the specific latent heat of fusion of the metal.

Submit your answer in Jg − 1 \text{ Jg}^{-1} .


The answer is 40.

Ashish Menon by Ashish Menon , 20, India

This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try refreshing the page, (b) enabling javascript if it is disabled on your browser and, finally, (c) loading the non-javascript version of this page . We're sorry about the hassle.

1 solution

Ashish Menon
Apr 7, 2016

Relevant wiki: Heat Transfer

Heat energy supplied by heater = P × t = 50 × ( 5 × 60 ) J ( Because 1 min = 60 sec ) = 15000 J Heat absorbed by material = m × L ⟹ 15000 = 375 × L ⟹ L = 15000 375 = 40 J/g \begin{aligned} \text{Heat energy supplied by heater} & = P × t\\ & = 50 × (5 × 60)J (\text{Because 1 min = 60 sec})\\ & = 15000J\\ \\ \text{Heat absorbed by material} & = m × L\\ \implies 15000 & = 375 × L\\ \implies L & = \dfrac{15000}{375}\\ & = \boxed{\text{40 J/g}} \end{aligned}

0 Helpful 0 Interesting 0 Brilliant 0 Confused

0 pending reports

×

Problem Loading...

Note Loading...

Set Loading...