The energy of a photon of light with wavelength $5000\,  \mathring A$ is approximately $2.5 eV$. This way the energy of an $X-$ ray photon with wavelength $1\, \mathring A $ would be

  • A
    $2.5/5000 eV$
  • B
    $2.5/{(5000)^2}eV$
  • C
    $2.5 \times 5000\;eV$
  • D
    $2.5 \times {(5000)^2}eV$

Similar Questions

A $5$ watt source emits monochromatic light of wavelength $5000\; \mathring A$. When placed $0.5\; m$ away, it liberates photoelectrons from a photosensitive metallic surface. When the source is moved to a distance of $1.0\;m$, the number of photo electrons liberated will

  • [AIPMT 2007]

Write equation of mass of photon. 

The threshold wavelength for photoelectric emission from a material is $5500\,\mathring A$. Photoelectrons will be emitted, when this material is illuminated with monochromatic radiation from a

$A.$ $75\,W$ infra-red lamp

$B.$ $10\,W$ infra-red lamp

$C.$ $75\,W$ ultra-violet lamp

$D.$ $10\,W$ ultra-violet lamp

Choose the correct answer from the options given below :

  • [JEE MAIN 2023]

A $2\,mW$ laser operates at a wavelength of $500\,nm.$ The number of photons that will be emitted per second is [Given Planck’s constant $h = 6.6 \times 10^{-34}\,Js,$ speed of light $c = 3.0\times 10^8\,m/s$ ]

  • [JEE MAIN 2019]

The beam of light has three wavelengths $4144 \,\mathring A$, $4972 \;\mathring A$ and $6216\; \mathring A$ with a total intensity of $3.6 \times$ $10^{-5}\,Wm ^2$ equally distributed amongst the three wavelengths. The beam falls normally on the area $1\,cm ^2$ of a clean metallic surface of work function $2.3\,eV$. Assume that there is no loss of light by reflection and that each energetically capable photon ejects one electron. Calculate the number of photoelectrons liberated in $2\,s$.