The photoelectric threshold for a certain metal surface is 330 Å. What is the maximum kinetic energy of photoelectron released, if any, by a radiation of wavelength 1100 Å ?
No electron is emitted
Wavelength of incident radiation is . Therefore, frequency of incident radiation is
Threshold wavelength is . Therefore, threshold frequency is
Since v < v0, no photoelectron is emitted.
An -particle and a deuteron projected with equal kinetic energies describe circular paths of radii r1 and r2 respectively in a uniform magnetic field. The ratio is
In a cyclotron the speed of a charged particle is increased by
A monoenergetic electron beam with electron speed of is subjected to a magnetic field of normal to the beam velocity. What is the radius of the circular path traced by the beam? Given .
Two parallel plates are placed 5 cm apart in an evacuated tube and a potential difference of 200 V is applied across them. What is the force experienced by an electron at rest in the region between the plates?
In Thomson’s experiment for determining , the potential difference between the cathode and the anode (in the accelerating column) is the same as that between the deflecting plates (in the region of crossed fields). If the potential difference is doubled, by what factor should the magnetic field be increased to ensure that the electron beam remains undeflected?
In Millikan’s oil drop experiment, a charged oil drop of mass is held stationary between two parallel plates 6 mm apart by applying a potential difference of 1200 V between them. How many excess electrons does the oil drop carry? Take g = 10 ms–2.
In Millikan’s oil drop experiment, an oil drop carrying a charge q falls with a terminal velocity v0 when there is no electric field between the plates. An electric field E is applied to keep it stationary. What additional charge should the oil drop acquire so that it begins to move upwards with a velocity 2v0 in the same electric field?
A metal whose work function is 3.31 eV is illuminated by light ofwavelength . What is the threshold frequency for photoelectric emission? Take
What is the maximum energy of photoelectrons emitted from the metal.
When a point source of light is at a distance of 50 cm from a photoelectric cell, the cut-off voltage is found to be V0. If the same source is placed at a distance of 1 m from the cell, the cut-off voltage will be