Question

Match the following

List - I	List - II
a) Fraunhofer lines	e) Newtons law of Cooling
b) Black body	f) Kirchhoff's law
c) Specific heat of a liquid	g) Ferry
d) Thermal conductivity	h) Searles apparatus of a metal

• A. $a\to g;b\to f;c\to e;d\to h$
• B. $a\to f;b\to g;c\to e;d\to h$
• C. $a\to e;b\to h;c\to g;d\to f$
• D. $a\to h;b\to e;c\to g;d\to f$

Answer 1

Answer: (B)

$a\to f;b\to g;c\to e;d\to h$

a) Kirchhoff had noticed that several Fraunhofer lines coincide with characteristic emission lines identified in the spectra of heated elements and deduced that dark lines in the solar spectrum are caused by absorption by chemical elements. in the Solar atmosphere.
b) A fine hole in a double walled spherical cavity, evacuated and painted black, represents Ferry's black body.
c) Using Newton law of cooling we have
$\frac{dQ}{dt}=-K(\theta -{\theta }_o)$
or
$mc\frac{d\theta }{dt}=-K(\theta -{\theta }_o)$
or
$\frac{d\theta }{dt}=-\frac{K}{mc}(\theta -{\theta }_o)$($c$ is the specific heat)

d) Searle's apparatus measures the thermal conductivity of a solid.