Monochromatic light of frequency  is produced by a laser. The power emitted is . What is the energy of a photon in the light beam?


Correct option is

The energy of a photon of frequency v is 






A direct X-ray photograph of the intestines is not generally taken by the radiologists because :


X-rays which can penetrate through longer distance in substances are called.


The target in an X-rays tube should be a:


The maximum frequency of the X-rays produced in an X-ray tube


Which one of the following parameters of the emitted X-rays increases when the potential difference between the electrodes of an X-ray tube is increased?  


Calculate the energy of a photon, in electron-volt (eV) and in watt-hour (W h), of wavelength 6600 Å. 


An X-rays tube produces a continuous spectrum of radiation with its short wavelength end at 0.45 Å. What is the maximum energy of a photon in the radiation? What is the order of accelerating voltage (for electrons) required in such a tube? 




In an accelerator experiment on high-energy collisions of the electrons with positrons, a certain event is interpreted as the annihilation of an electron-positron pair of total energy 10.2 BeV into two -rays of equal energy. Find the wavelength associated with each -ray. 


Energy from Sun is received on earth at the rate of . If average wavelength of solar light is taken as 550 nm, then how many photons are received on earth per meter2 per second? 


A beam of green light  gives energy at the rate of 1 Js–1 to a surface where it is fully absorbed. How many photons reach the surface per second? If every 100 photons emit one electron, how much current will flow from the surface?