1
GATE ME 2017 Set 2
+1
-0.3
The emissive power of a blackbody is $$P.$$ If its absolute temperature is doubled, the emissive power becomes
A
$$2P$$
B
$$4P$$
C
$$8P$$
D
$$16$$$$P$$
2
GATE ME 2016 Set 2
+1
-0.3
Consider the radiation heat exchange inside an annulus between two very long concentric cylinders. The radius of the outer cylinder is $${R_0}$$ and that of the inner cylinder is $${R_i}$$ . The radiation view factor of the outer cylinder onto itself is
A
$$1 - \sqrt {{{{R_i}} \over {{R_0}}}}$$
B
$$\sqrt {1 - {{{R_i}} \over {{R_0}}}}$$
C
$$1 - {\left( {{{{R_i}} \over {{R_0}}}} \right)^{1/3}}$$
D
$$1 - {{{R_i}} \over {{R_0}}}$$
3
GATE ME 2012
+1
-0.3
For an opaque surface, the absorptivity $$\left( \alpha \right),$$ transmissivity $$\left( \tau \right)$$ and reflectivity $$\left( \rho \right)$$ are related by the equation:
A
$$\alpha + \rho = \tau$$
B
$$\rho + \alpha + \tau = 0$$
C
$$\alpha + \rho = 1$$
D
$$\alpha + \rho = 0$$
4
GATE ME 2005
+1
-0.3
The following figure was generated from experimental data relating spectral black body emissive power to wave length at three temperatures $${T_1},{T_2}$$ and $${T_3}\left( {{T_1} > {T_2} > {T_3}} \right).$$

The conclusion is that the measurements are

A
correct because the maximum in $${E_{b\lambda }}$$ show the correct trend
B
correct because Planck's law is satisfied
C
wrong because the Stephen Boltzmannn law is not satisfied
D
wrong because Wien's displacement law is not satisfied
GATE ME Subjects
EXAM MAP
Medical
NEET