Quiz 27: Quantum Physics

Physics & Astronomy

The light reflection from the object surface is observed to determine the shape of the object. The objects inside a kiln will be very hot and are shining with brilliant red. So, the radiation emitted from the object is much stronger than the reflected radiation. The collection of objects inside kiln including walls of kiln, shining equally with emitted radiation and also reflected light is weak as compared to the emitted radiation. As a result, we cannot observe the objects inside a hot kiln.

(a) The expression for peak wavelength of radiation given by Wien's displacement law, img Here, img is the surface temperature of star. Rearrange the equation for img . img Convert the unit of img from nm to m, img Substitute img for img in the equation img and solve for img . img Round off to one significant figure, the surface temperature of red giant star is img . (b) Use Wein's displacement law, the surface temperature of the bluish-white star is as follows. img Convert the unit of img from nm to m, img Substitute img for img in the equation img and solve for img . img Round off to one significant figure, the surface temperature of the bluish-white star is img .

A microscope can be used to see the details of smaller object which is less than the wavelength of the light waves. Electrons are moving with a kinetic energy of several electron volts whose wavelengths less than a nanometer. This wavelength is much smaller than the wavelengths of visible light. So, the particles with much smaller size can be resolved by using electron microscope whereas compared with the optical microscope.