Home
Class 12
PHYSICS
Photons of wavelength lambda are inciden...

Photons of wavelength `lambda` are incident on a metal. The most energetic electrons ejected from the metal are bent into a circular arc of radius R by a perpendicular magnetic field having magnitude B. The work function of the metal is……………………

A

`(hc)/(lambda) - m_(e)+ (e^(2) B^(2)R^(2))/(2m_(e))`

B

`(hc)/(lambda) + 2m_(e) [(eBR)/(2m_(e))]^(2)`

C

`(hc)/(lambda) - m_(e) c^(2) - (e^(2)B^(2)R^(2))/(2m_(e))`

D

`(hc)/(lambda) - 2m_(e) [(eBR)/(2m_(e))]^(2)`

Text Solution

Verified by Experts

The correct Answer is:
A
`(hc)/(lambda) - 2m_(e) [(eBR)/(2m_(e))]^(2)`
Magnetic lorertz force = C entripetal force
`BqV = (mv^(2))/(R)`
`therefore " "V = (qBR)/(m) = (eBR)/(m)`
From Einstein .s photo electric equation
`KE_(max) = (hc)/(lambda) - phi`
` phi = (hc)/(lambda) - (1)/(2)m_(e)V^(2) = (hc)/(lambda) - (1)/(2)m_(e) ((eBR)/(m_(e)))^(2)`
` phi = (hc)/(lambda) - 2m_(e) (eBR)/(2m_(e))^(2)`
Promotional Banner

Topper's Solved these Questions

  • SAMPLE PAPER -12

    FULL MARKS|Exercise PART-II|9 Videos

  • SAMPLE PAPER -12

    FULL MARKS|Exercise PART-III|9 Videos

  • SAMPLE PAPER -10 (SOLVED)

    FULL MARKS|Exercise PART - IV|10 Videos

  • SAMPLE PAPER -13

    FULL MARKS|Exercise PART - IV|10 Videos

Similar Questions

Explore conceptually related problems

Photons of wavelength lambda are incident on a metal. The most energies electrons ejected from the metal are bent into a circular arc of radius R by a perpendicular magnetic field having magnitude B. The work function of the metal is

In photoelectric effect, electrons are ejected from metals, if the incident light has a certain minimum

Light of wavelength 500 nm is incident on a metal with work function 2.28 eV. The de Broglie wavelength of the emitted electron is :

A beam of 450 nm light is incident on a metal having work function 2.0 eV and placed in a magnetic field B. The most energetic electrons emitted perpendicular to the field are bent in circular arcs of radius 20 cm. Find the value of B.

Light of wavelength lambda falls on metal having work functions hc//lambda_(0) . Photoelectric effect will take place only if :

When the energy of the incident radiation is increased by 20%, the kinetic energy of the photoelctrons emitted from a metal surface increased from 0.5eV to 0.8eV . The work function of the metal is:

Light from balmer series of hydrogen is able to eject photoelectron from a metal what can be the maximum work function of the metal?

A metallic metre sitck moves with a velocity of 2 ms ^(-1) in a direction perpendicular to its length and perpendicular to a uniform magnetic field of magnitude 0.2 T. Find the emf indcued between the ends of the stick.

Light of wavelength 3500 A^(@) is incident on two metals A and B. Which metal will yield photoelectrons, if their work functions are 4.2 eV and 1.9 eV respectively ?