149448 An experimenter needs to heat a small sample to temperature $900 \mathrm{~K}$, but the only available large object has maximum temperature of $600 \mathrm{~K}$. Could the experimenter heat the sample to $900 \mathrm{~K}$ by using a large lens to concentrate the radiation from the large object onto the sample as shown below?

149485 Consider two identical iron spheres $P$ and $Q$, one which lie on a thermally insulating plate, while the other hangs from an insulated thread. Equal amount of heat $(\Delta Q)$ is supplied to the two spheres. Then,

149448 An experimenter needs to heat a small sample to temperature $900 \mathrm{~K}$, but the only available large object has maximum temperature of $600 \mathrm{~K}$. Could the experimenter heat the sample to $900 \mathrm{~K}$ by using a large lens to concentrate the radiation from the large object onto the sample as shown below?

149485 Consider two identical iron spheres $P$ and $Q$, one which lie on a thermally insulating plate, while the other hangs from an insulated thread. Equal amount of heat $(\Delta Q)$ is supplied to the two spheres. Then,