मराठी
कर्नाटक बोर्ड पी.यू.सी.पीयूसी विज्ञान इयत्ता ११

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. - Physics

Advertisements
Advertisements

प्रश्न

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?

बेरीज

उत्तर

According to Paschen's equation, sparking potential (V) is a function of the product of pressure (P) inside the tube and the length (d) of the tube.

V = f(Pd)

As the sparking potential is same in both the tubes, the product of P and d must be equal for both the tubes.

Length of the smaller tube, ds = 10 cm

Pressure inside the smaller tube, Ps = 1.0 mm of mercury

Let the pressure inside the longer  tube, Pl,, be x mm of mercury.

Length of the longer tube, dl = 20 cm

\[P_s  d_s  =  P_l  d_l \]

\[\frac{P_s}{P_l} = \frac{d_s}{d_l}\]

\[\frac{10}{20} = \frac{1  mm}{x}\]

\[ \Rightarrow \frac{20}{10} = \frac{1  mm}{x}\]

\[ \Rightarrow   x = \frac{1  mm}{2} = 0 . 5  mm\]

Hence, the pressure in the longer tube is 0.5 mm of Hg.

shaalaa.com
  या प्रश्नात किंवा उत्तरात काही त्रुटी आहे का?
पाठ 19: Electric Current through Gases - Exercises [पृष्ठ ३५३]

APPEARS IN

एचसी वर्मा Concepts of Physics Vol. 2 [English] Class 11 and 12
पाठ 19 Electric Current through Gases
Exercises | Q 4 | पृष्ठ ३५३

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.


Cathode rays constitute a stream of _______________ .


Cathode rays are passing through a discharge tube. In the tube, there is ______________ .


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 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?


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 ______.


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×