A substances may be athermanous or diathermanous for certain wavelength, while good absorber for other wavelength. Explain.

Define athermanous and substance diathermanous.

White light is used to illuminate the two slits in a Young's double slit experment . The separation between the slits is b and the screen is at a distance d ( d >> b ) from the slits . At a point on the screen directly in front of one of the slits , certain wavelengths are missing . Some of these missing wavelengths are

There are materials which absorb photons of shorter wavelength and emit photons of longer wavelength. Can there be stable substances which absorb photons of larger wavelength and emit light of shorter wavelength

A prism of a refracting angle 60^(@) is made with a material of refractive index mu . For a certain wavelength of light, the angle of minimum deviation is 30^(@) . For this wavelength, the value of mu of material is

The photoelectric work function of the emitter of a photoelectric cell is 2 eV. When the emitter is irradiated by monochromatic light of certain wavelength,the photoelectric current can just be reduced to zero by applying a stopping potential of 1.5 volt. Determine the wavelength of incident .

Estimate the distance for which ray optics is good approximation for an aperture of 4 mm and wavelength 400 nm .

The photoelectric work function of the emitter of photoelectric cell is 2 eV.Whenemitter is irradiated by monochromatic light of certain wavelength, the photoelectric current can just be reduced to zero by applying stopping potential of 1.5 V. Find the wavelength of incident light.

Paragraph based question Read the following paragraphs and answer the questions based on it. After the death of apex consumers, their energy becomes available to the decomposers. Fungi and other micro-organisms decompose the bodies of dead animals. They are called decomposers. In the process of obtaining food from the remains of organisms, decomposers convert them into simple carbon compounds. These substances easily mix with air, water and soil from where they are again absorbed by plants and incorporated into the food chain. How is energy and other nutrients circulated in the ecosystem?

Paragraph based question Read the following paragraphs and answer the questions based on it. After the death of apex consumers, their energy becomes available to the decomposers. Fungi and other micro-organisms decompose the bodies of dead animals. They are called decomposers. In the process of obtaining food from the remains of organisms, decomposers convert them into simple carbon compounds. These substances easily mix with air, water and soil from where they are again absorbed by plants and incorporated into the food chain. Name the decomposers. Where are they found?