Which of the following electromagnetic radiations has the longest wavelength?

A black body radiates energy at the rate of $E\,\,W{m^{ - 2}}$ at a high temperature T K. When the temperature is reduced to $\left( {\frac{T}{2}} \right)K$ the radiant energy is

Two identical bodies have temperatures ${277^0}C$ and ${67^0}C$ . If the surroundings temperature is ${27^0}C$ the ratio of loss of heats of the two bodies during the same interval of time is(approximately)

A body initially at ${80^0}C$ cools to ${64^0}C$ in 5 min and to ${52^0}C$ in 10 min. the temperature of the surrounding is

If the temperature difference on the two sides of a wall increases from ${100^0}C$ to ${200^0}C$, its thermal conductivity

The maximum wavelength of radiation emitted at 2000K is $4\mu m$. What will be the maximum wavelength of radiation emitted at 2400 K

The rate of radiation of a black body at ${0^0}C$ is $EJ/s.$. The rate of radiation of this black body at ${273^0}C$ will be

A cane is taken out from a refrigerator at ${0^0}C$. The atmospheric temperature is ${25^0}C$. If ${t_1}$ is the time taken to heat from ${0^0}C$ to ${5^0}C$ and ${t_2}$ is the time taken from ${10^0}C$ to ${15^0}C$, then

Which is the following is more close to a black body?

Two bulbs has filaments of lengths, emissivity and diameters in the ratio of 2:1. If ratio of their powers is 1:2 then, ratio of their temperatures is

Let there be four articles having colours blue, red, black and white. When they are heated together and allowed to cool, which article cool at the earliest