Question

In a discharge tube ionisation of enclosed gas is produced due to collisions between

A. positive ions and neutral atoms/molecules
B. negative electrons and neutral atoms/molecules  
C. photons and neutral atoms/molecules
D. neutral gas atoms/molecules
Answer :   negative electrons and neutral atoms/molecules
Solution :
In a discharge tube, after being accelerated though a high potential difference the ions in the gas strike the cathode with huge kinetic energy. This collision liberates electrons from the cathode. These free electrons can further liberate ions from gas molecules through collisions. The positive ions are attracted towards the cathode and negatively charged electrons move towards anode. Thus, ionisation of gas results.

Releted MCQ Question on
Modern Physics >> Dual Nature of Matter and Radiation

Releted Question 1

A particle of mass $$M$$ at rest decays into two particles of masses $${m_1}$$ and $${m_2},$$ having non-zero velocities. The ratio of the de Broglie wavelengths of the particles, $$\frac{{{\lambda _1}}}{{{\lambda _2}}},$$  is

A. $$\frac{{{m_1}}}{{{m_2}}}$$
B. $$\frac{{{m_2}}}{{{m_1}}}$$
C. 1.0
D. $$\frac{{\sqrt {{m_2}} }}{{\sqrt {{m_1}} }}$$
View Answer
Releted Question 2

A proton has kinetic energy $$E = 100\,keV$$   which is equal to that of a photon. The wavelength of photon is $${\lambda _2}$$ and that of proton is $${\lambda _1}.$$ The ration of $$\frac{{{\lambda _2}}}{{{\lambda _1}}}$$  is proportional to

A. $${E^2}$$
B. $${E^{\frac{1}{2}}}$$
C. $${E^{ - 1}}$$
D. $${E^{ - \frac{1}{2}}}$$
View Answer
Releted Question 3

A beam of electron is used in an YDSE experiment. The slit width is $$d.$$ When the velocity of electron is increased, then

A. no interference is observed
B. fringe width increases
C. fringe width decreases
D. fringe width remains same
View Answer
Releted Question 4

Formation of covalent bonds in compounds exhibits

A. wave nature of electron
B. particle nature of electron
C. both wave and particle nature of electron
D. none of these
View Answer

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Dual Nature of Matter and Radiation

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