149505 There discs 1,2 and 3 having radii $2 \mathrm{~m}, 4 \mathrm{~m}$ and 6m respectively, are coated with carbon black on their outer surfaces. The wavelengths corresponding to maximum intensity are $300 \mathrm{~nm}, 400 \mathrm{~nm}$ and $500 \mathrm{~nm}$ respectively. The power radiated by them is $Q_{1}, Q_{2}$, and $Q_{3}$ respectively. Then which one is true?
149506
If the emissive power of black surface at same temperature is $400 \mathrm{~W} / \mathrm{m}^{2}$, the emissive and absorptive powers of the surface assuming it was initially ordinary surface, are
(Given, Mass of the body $\mathrm{m}=4.2 \mathrm{~kg}$, area of body $=5 \times 10^{-2} \mathrm{~m}^{2}$,
rate of cooling $\frac{\mathrm{d} \theta}{\mathrm{dt}}=\frac{1}{12} \times 10^{-2} \mathrm{C} / \mathrm{min}$,
specific heat $s=420 \mathrm{~J} / \mathrm{kg}^{0} \mathrm{C}$ )
149510 A black rectangular surface of area $A$ emits energy $E$ per second at $27^{\circ} \mathrm{C}$. If length and breadth is reduced to $\left(\frac{1}{3}\right)^{\text {rd }}$ of initial value and temperature is raised to $327^{\circ} \mathrm{C}$ then energy emitted per second becomes
149505 There discs 1,2 and 3 having radii $2 \mathrm{~m}, 4 \mathrm{~m}$ and 6m respectively, are coated with carbon black on their outer surfaces. The wavelengths corresponding to maximum intensity are $300 \mathrm{~nm}, 400 \mathrm{~nm}$ and $500 \mathrm{~nm}$ respectively. The power radiated by them is $Q_{1}, Q_{2}$, and $Q_{3}$ respectively. Then which one is true?
149506
If the emissive power of black surface at same temperature is $400 \mathrm{~W} / \mathrm{m}^{2}$, the emissive and absorptive powers of the surface assuming it was initially ordinary surface, are
(Given, Mass of the body $\mathrm{m}=4.2 \mathrm{~kg}$, area of body $=5 \times 10^{-2} \mathrm{~m}^{2}$,
rate of cooling $\frac{\mathrm{d} \theta}{\mathrm{dt}}=\frac{1}{12} \times 10^{-2} \mathrm{C} / \mathrm{min}$,
specific heat $s=420 \mathrm{~J} / \mathrm{kg}^{0} \mathrm{C}$ )
149510 A black rectangular surface of area $A$ emits energy $E$ per second at $27^{\circ} \mathrm{C}$. If length and breadth is reduced to $\left(\frac{1}{3}\right)^{\text {rd }}$ of initial value and temperature is raised to $327^{\circ} \mathrm{C}$ then energy emitted per second becomes
149505 There discs 1,2 and 3 having radii $2 \mathrm{~m}, 4 \mathrm{~m}$ and 6m respectively, are coated with carbon black on their outer surfaces. The wavelengths corresponding to maximum intensity are $300 \mathrm{~nm}, 400 \mathrm{~nm}$ and $500 \mathrm{~nm}$ respectively. The power radiated by them is $Q_{1}, Q_{2}$, and $Q_{3}$ respectively. Then which one is true?
149506
If the emissive power of black surface at same temperature is $400 \mathrm{~W} / \mathrm{m}^{2}$, the emissive and absorptive powers of the surface assuming it was initially ordinary surface, are
(Given, Mass of the body $\mathrm{m}=4.2 \mathrm{~kg}$, area of body $=5 \times 10^{-2} \mathrm{~m}^{2}$,
rate of cooling $\frac{\mathrm{d} \theta}{\mathrm{dt}}=\frac{1}{12} \times 10^{-2} \mathrm{C} / \mathrm{min}$,
specific heat $s=420 \mathrm{~J} / \mathrm{kg}^{0} \mathrm{C}$ )
149510 A black rectangular surface of area $A$ emits energy $E$ per second at $27^{\circ} \mathrm{C}$. If length and breadth is reduced to $\left(\frac{1}{3}\right)^{\text {rd }}$ of initial value and temperature is raised to $327^{\circ} \mathrm{C}$ then energy emitted per second becomes
149505 There discs 1,2 and 3 having radii $2 \mathrm{~m}, 4 \mathrm{~m}$ and 6m respectively, are coated with carbon black on their outer surfaces. The wavelengths corresponding to maximum intensity are $300 \mathrm{~nm}, 400 \mathrm{~nm}$ and $500 \mathrm{~nm}$ respectively. The power radiated by them is $Q_{1}, Q_{2}$, and $Q_{3}$ respectively. Then which one is true?
149506
If the emissive power of black surface at same temperature is $400 \mathrm{~W} / \mathrm{m}^{2}$, the emissive and absorptive powers of the surface assuming it was initially ordinary surface, are
(Given, Mass of the body $\mathrm{m}=4.2 \mathrm{~kg}$, area of body $=5 \times 10^{-2} \mathrm{~m}^{2}$,
rate of cooling $\frac{\mathrm{d} \theta}{\mathrm{dt}}=\frac{1}{12} \times 10^{-2} \mathrm{C} / \mathrm{min}$,
specific heat $s=420 \mathrm{~J} / \mathrm{kg}^{0} \mathrm{C}$ )
149510 A black rectangular surface of area $A$ emits energy $E$ per second at $27^{\circ} \mathrm{C}$. If length and breadth is reduced to $\left(\frac{1}{3}\right)^{\text {rd }}$ of initial value and temperature is raised to $327^{\circ} \mathrm{C}$ then energy emitted per second becomes
149505 There discs 1,2 and 3 having radii $2 \mathrm{~m}, 4 \mathrm{~m}$ and 6m respectively, are coated with carbon black on their outer surfaces. The wavelengths corresponding to maximum intensity are $300 \mathrm{~nm}, 400 \mathrm{~nm}$ and $500 \mathrm{~nm}$ respectively. The power radiated by them is $Q_{1}, Q_{2}$, and $Q_{3}$ respectively. Then which one is true?
149506
If the emissive power of black surface at same temperature is $400 \mathrm{~W} / \mathrm{m}^{2}$, the emissive and absorptive powers of the surface assuming it was initially ordinary surface, are
(Given, Mass of the body $\mathrm{m}=4.2 \mathrm{~kg}$, area of body $=5 \times 10^{-2} \mathrm{~m}^{2}$,
rate of cooling $\frac{\mathrm{d} \theta}{\mathrm{dt}}=\frac{1}{12} \times 10^{-2} \mathrm{C} / \mathrm{min}$,
specific heat $s=420 \mathrm{~J} / \mathrm{kg}^{0} \mathrm{C}$ )
149510 A black rectangular surface of area $A$ emits energy $E$ per second at $27^{\circ} \mathrm{C}$. If length and breadth is reduced to $\left(\frac{1}{3}\right)^{\text {rd }}$ of initial value and temperature is raised to $327^{\circ} \mathrm{C}$ then energy emitted per second becomes