Advertisements
Advertisements
प्रश्न
Define the term ‘stopping potential’ in relation to photo-electric effect.
Advertisements
उत्तर
If we increase the negative potential of the collector, the photoelectric current decreases rapidly. At a certain critical value of the negative potential of the collector, the photoelectric current becomes zero. This potential is called stopping potential or cut-off potential and it depends on the frequency of the incident radiation, but independent of its intensity.
APPEARS IN
संबंधित प्रश्न
State clearly how photoelectric equation is obtained using the photon pictu.re of electromagnetic radiation.
Cathode rays constitute a stream of _______________ .
Which of the following is true for a cathode ray?
(a) It travels in a straight line.
(b) It emits an X-ray when it strikes a metal.
(c) It is an electromagnetic wave.
(d) It is not deflected by a magnetic field.
The saturation current in a triode valve can be changed by changing _____________ .
A molecule of a gas, filled in a discharge tube, gets ionised when an electron is detached from it. An electric field of 5.0 kV m−1 exists in the vicinity of the event. (a) Find the distance travelled by the free electron in 1 µs, assuming there's no collision. (b) If the mean free path of the electron is 1.0 mm, estimate the time of transit of the free electron between successive collisions.
The mean free path of electrons in a gas in a discharge tube is inversely proportional to the pressure inside it. The Crookes dark space occupies half the length of the discharge tube when the pressure is 0.02 mm of mercury. Estimate the pressure at which the dark space will fill the whole tube.
On what factor does the maximum kinetic energy of the photoelectrons in a photo cell depend?
Which of the following proves particle nature of light?
Assertion A: The photoelectric effect does not takes place, if the energy of the incident radiation is less than the work function of a metal.
Reason R: Kinetic energy of the photoelectrons is zero, if the energy of the incident radiation is equal to the work function of a metal.
The electric field at a point associated with a light wave is given by
E = 200[sin(6 × 1015)t + sin(9 × 1015)t]Vm-1
Given: h = 4.14 × 10-15 eVs.
If this light falls on a metal surface having a work function of 2.50eV, the maximum kinetic energy of the photoelectrons will be ______.
