Home
Class 12
PHYSICS
A horizontal cesium plate is moved verti...

A horizontal cesium plate is moved vertically downward at a constant speed v in a room full of radiation of wavelength 250nm and above. What should be the minimum value of v so that the vertically upward component of velocity is nonpositive for each photoelectron?

Text Solution

Verified by Experts

When `lambda = 250nm `
Energy of Photon
` = hc / lambda = 1240 / 250 = 4.96 eV`
`:. K.E. = hc / lambda - W = 4.96 - 1.9 eV `
` = 3.06 eV `
Velocity to be non positive for each photo electron . The minimum value of velocity of plate should be equal to velocity of photo electron
`:. Velocity of photo electron `
` = (sqrt 2KE / M ) = (sqrt 2 xx 3.06 xx 1.6 xx 10^(-19) / 9.1 xx 10^(-31)) `
` = 1.04 xx 10^(6) m/sec`.
Promotional Banner

Topper's Solved these Questions

  • PHOTO ELECTRIC EFFECT AND WAVE PARTICLE DUALITY

    HC VERMA|Exercise Exercise|2 Videos

  • PHOTO ELECTRIC EFFECT AND WAVE PARTICLE DUALITY

    HC VERMA|Exercise Objective 2|7 Videos

  • PERMANENT MAGNETS

    HC VERMA|Exercise Exercises|25 Videos

  • PHOTOMETRY

    HC VERMA|Exercise Exercises|16 Videos

Similar Questions

Explore conceptually related problems

For the situation shown in the figure, what should be the value of force required to move the rod with constant velocity v = 2 m/s ?

A balloon starts ascending from the ground at a constant speed of 25 m//s . After 5 s, a bullet is shot vertically upwards from the ground. (i) What should be the minimun speed of the bullet so that it may reach the balloon? (ii) The bullet is shot at twise the speed calculated in (i). Find the height at which it passes the balloon.

A glass wind screen whose inclination with the vertical can be changed is mounted on a car. The moves horizontally with a speed of 2m//s . At what angle alpha with the vertical should the wind screen placed so that the rain drops falling vertically downwards with velcoity 6m//s strike the wind screen perpendicularly?

Two blocks of mass m_(1)=10kg and m_(2)=5kg connected to each other by a massless inextensible string of length 0.3m are placed along a diameter of the turntable. The coefficient of friction between the table and m_(1) is 0.5 while there is no friction between m_(2) and the table. the table is rotating with an angular velocity of 10rad//s . about a vertical axis passing through its center O . the masses are placed along the diameter of the table on either side of the center O such that the mass m_(1) is at a distance of 0.124m from O . the masses are observed to be at a rest with respect to an observed on the tuntable (g=9.8m//s^(2)) . (a) Calculate the friction on m_(1) (b) What should be the minimum angular speed of the turntable so that the masses will slip from this position? (c ) How should the masses be placed with the string remaining taut so that there is no friction on m_(1) .

A particle A is projected with speed v_(A) from a point making an angle 60^(@) with the horizontal. At the same instant, a second particle B is thrown vertically upwards from a point directly below the maximum hieght point of parabolic path of A with velocity v_(B) . If the two particles collide then the ratio of v_(A)//v_(B) should be

A rocket of mass 1000 kg is to be projected vertically upwards. The gases are exhausted vertically downwards with velocity 100m//s with respect to the rocket. (What is the minimum rate of burning fuel, so as to just lift the rocket upwards against the gravitational attraction?) (Take g=10m//s^(2) )

If the container filled with liquid gets accelerated horizontally or vertically, pressure in liquid gets changed. In liquid ( a_(y) ) for calculation of pressure, effective g is used. A closed box horizontal base 6 m by 6 m and a height 2m is half filled with liquid. It is given a constant horizontal acceleration g//2 and vertical downward acceleration g//2 . What is the value of vertical acceleration of box for given horizontal acceleration (g//2) , so that no part of the bottom of the box is exposed?

Two balls are fired form ground level, a distance d apart. The right one is fired vertically with speed v . You wish to simultancously fire the left one at appropriate velocity u so that collides with the right ball when they reach their highest point. Value of horizontal (u_(x)) and vertical (u_(y)) components of u are respectively :- .

A circus wishes to develop a new clown act. Fig. (1) shows a diagram of the proposed setup. A clown will be shot out of a cannot with velocity v_(0) at a trajectory that makes an angle theta=45^(@) with the ground. At this angile, the clown will travell a maximum horizontal distance. The cannot will accelerate the clown by applying a constant force of 10, 000N over a very short time of 0.24s . The height above the ground at which the clown begins his trajectory is 10m . A large hoop is to be suspended from the celling by a massless cable at just the right place so that the clown will be able to dive through it when he reaches a maximum height above the ground. After passing through the hoop he will then continue on his trajectory until arriving at the safety net. Fig (2) shows a graph of the vertical component of the clown's velocity as a function of time between the cannon and the hoop. Since the velocity depends on the mass of the particular clown performing the act, the graph shows data for serveral different masses. If a clown holds on to hoop instead of passing through it, what is the position of the cable so that he doesn't hit his head on the ceiling as he swings upward?

A circus wishes to develop a new clown act. Fig. (1) shows a diagram of the proposed setup. A clown will be shot out of a cannot with velocity v_(0) at a trajectory that makes an angle theta=45^(@) with the ground. At this angile, the clown will travell a maximum horizontal distance. The cannot will accelerate the clown by applying a constant force of 10, 000N over a very short time of 0.24s . The height above the ground at which the clown begins his trajectory is 10m . A large hoop is to be suspended from the celling by a massless cable at just the right place so that the clown will be able to dive through it when he reaches a maximum height above the ground. After passing through the hoop he will then continue on his trajectory until arriving at the safety net. Fig (2) shows a graph of the vertical component of the clown's velocity as a function of time between the cannon and the hoop. Since the velocity depends on the mass of the particular clown performing the act, the graph shows data for serveral different masses. If the clown's mass is 80 kg , what initial velocity v_(0) will have as he leaves the cannot?

HC VERMA-PHOTO ELECTRIC EFFECT AND WAVE PARTICLE DUALITY-Exercises
  1. Find the maximum kinetic energy of the photoelectrons ejected when lig...

    Text Solution

    |

  2. The work function of a photoelectric material is 4.0 e V. (a) What i...

    Text Solution

    |

  3. Find the maximum magnitude of the linear momentum of a photoelectron e...

    Text Solution

    |

  4. When a metal plate is exposed to a monochromatic beam of light of wave...

    Text Solution

    |

  5. In an experiment on photoelectric effect, the stopping potential is me...

    Text Solution

    |

  6. The electric field associated with a monochromataic beam of light beco...

    Text Solution

    |

  7. The electric field associated with a light wave is given by E= E0 sin...

    Text Solution

    |

  8. The electric field at a point associated with a light wave is E=(100Vm...

    Text Solution

    |

  9. A monochromatic light source of intensity 5 m W emits (8xx10^15) photo...

    Text Solution

    |

  10. A photographic film is coated with a silver bromide layer. When light ...

    Text Solution

    |

  11. In an experiment on photoelectric effect light of wavelength 400 nm is...

    Text Solution

    |

  12. A silver ball of radius 4.8 cn is suspended by a thread in a cacuum ch...

    Text Solution

    |

  13. In an experiment on photoelectric effect, the emitter and the collecto...

    Text Solution

    |

  14. In the following arrangement y = 1.0 mm , d = 0.24 mm and D = 1.2 m. T...

    Text Solution

    |

  15. In a photoelectric experiment, the collector plate is at 2.0 V with re...

    Text Solution

    |

  16. A small piece of cesium metal(work function= 1.9eV) is kept at a dista...

    Text Solution

    |

  17. Consider the situation of the previous problem. Consider the fastest e...

    Text Solution

    |

  18. A horizontal cesium plate is moved vertically downward at a constant s...

    Text Solution

    |

  19. A small metal plate of work function phi is kept at a distance r from ...

    Text Solution

    |

  20. A light beam of wavelength 400 nm is incident on a metal of work- func...

    Text Solution

    |