1
AIPMT 2009
+4
-1
A black body at 227oC radiates heat at the rate of 7 cals/cm2s. At a temperature of 727oC, the rate of heat radiated in the same units will be
A
50
B
112
C
80
D
60
2
AIPMT 2009
+4
-1
The two ends of a rod of length L and a uniform cross-sectional area A are Kept at two temperatures T1 and T2 (T1 > T2). The rate of heat transfer, $${{dQ} \over {dt}}$$ through the rod in a steady state is given by :
A
$${{dQ} \over {dt}} = {{k\left( {{T_1} - {T_2}} \right)} \over {LA}}$$
B
$${{dQ} \over {dt}} = kLA({T_1} - {T_2})$$
C
$${{dQ} \over {dt}} = {{kA\left( {{T_1} - {T_2}} \right)} \over L}$$
D
$${{dQ} \over {dt}} = {{kL\left( {{T_1} - {T_2}} \right)} \over A}$$
3
AIPMT 2008
+4
-1
On a new scale of temperature (which is linear) and called the W scale, the freezing and boiling points of water are 39oW and 239oW respectively. What will be the temperature on the new scale, corresponding to a temperature of 39oC on the Celsius scale ?
A
200oW
B
139oW
C
78oW
D
117oW
4
AIPMT 2007
+4
-1
Assuming the sun to have a spherical outer surface of radius r, radiating like a black body at temperature toC, the power received by a unit surface, (normal to the incident rays) at a distance R from the centre of the sun is
where $$\sigma$$ is the Stefan's constant.
A
$${{{r^2}\sigma {{\left( {t + 273} \right)}^4}} \over {4\pi {R^2}}}$$
B
$${{16{\pi ^2}{r^2}\sigma {t^4}} \over {{R^2}}}$$
C
$${{{r^2}\sigma {{\left( {t + 273} \right)}^4}} \over {{R^2}}}$$
D
$${{4\pi {r^2}\sigma {t^4}} \over {{R^2}}}$$
EXAM MAP
Medical
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