Advertisements
Advertisements
प्रश्न
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.
उत्तर
(a) It travels in a straight line.
(b) It emits an X-ray when it strikes a metal.
A cathode ray travels in a straight line. When cathode rays strike a solid metal, X-rays are emitted from the metal. When a cathode ray tube is brought in a magnetic field, the path of cathode rays gets deflected. Cathode rays are the matter waves that consists of electrons thus they are not electromagnetic waves.
APPEARS IN
संबंधित प्रश्न
Calculate the wavelength of radiation emitted when electron in a hydrogen atom jumps from n = `oo` to n = 1.
State clearly how photoelectric equation is obtained using the photon pictu.re of electromagnetic radiation.
Write the three salient features observed in photoelectric effect which can be explained using this equation.
Define the term ‘stopping potential’ in relation to photo-electric effect.
Cathode rays constitute a stream of _______________ .
Cathode rays are passing through a discharge tube. In the tube, there is ______________ .
The saturation current in a triode valve can be changed by changing _____________ .
A discharge tube contains helium at low pressure. A large potential difference is applied across the tube. Consider a helium atom that has just been ionised due to the detachment of an atomic electron. Find the ratio of the distance travelled by the free electron to that by the positive ion in a short time dt after ionisation.
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.
Two discharge tubes have identical material structures and the same gas is filled in them. The length of one tube is 10 cm and that of the other tube is 20 cm. Sparking starts in both the tubes when the potential difference between the cathode and the anode is 100 V. If the pressure in the shorter tube is 1.0 mm of mercury, what is the pressure in the longer tube?
The saturation current from a thoriated-tungsten cathode at 2000 K is 100 mA. What will be the saturation current for a pure-tungsten cathode of the same surface area operating at the same temperature? The constant A in the Richardson-Dushman equation is 60 × 104 Am −2 K−2 for pure tungsten and 3.0 × 104 Am −2 k−2 for thoriated tungsten. The work function of pure tungsten is 4.5 eV and that of thoriated tungsten is 2.6 eV.
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?
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 ______.
