CBSE Questions for Class 12 Medical Physics Atoms Quiz 2 - MCQExams.com

Among the following, identify one that is antiparticle of itself :
  • Photon
  • Electron
  • Proton
  • $$\pi $$ -meson
The particle which has no antiparticle is
  • Proton
  • Electron
  • Neutron
  • Photon
If the radius of first Bohr orbit is $$'r'$$, then radius of second orbit will be
  • $$2r$$
  • $$\dfrac{r}{2}$$
  • $$4r$$
  • $$\sqrt{2r}$$
Cathode ray tube is operating at 5 kV. Then ,what is the K.E. acquired by the electrons ?
  • 5 eV
  • 5 MeV
  • 5 keV
  • 5 V
According to Bohr hypothesis, discrete quantity is
  • Momentum
  • Angular velocity
  • Potential energy
  • Angular momentum
As the orbit number increases, the distance between two consecutive orbits in an atom or ion having single electron
  • decreases
  • increases
  • remains the same
  • first increases and then becomes constant
For electron moving in $$n$$ th orbit of the atom, the angular velocity is proportional to:
  • $$n$$
  • $$\dfrac{1}{n}$$
  • $$n^{3}$$
  • $$\dfrac{1}{n^{3}}$$
The visible region of hydrogen spectrum was first studied by
  • Lyman
  • Balmer
  • Pfund
  • Brackett
The angular momentum of an electron in hydrogen atom is proportional to
  • $$\sqrt{r}$$
  • $$\dfrac{1}{r}$$
  • $$r^{2}$$
  • $$\dfrac{1}{\sqrt{r}}$$
A strong argument for particle nature of cathode rays is that they
  • Produce fluorescence
  • Travel through vacuum
  • Get deflected by electric and magnetic fields
  • Cast shadows
The visible region of hydrogen spectrum was first studied by
  • Lyman
  • Balmer
  • Pfund
  • Brakett
The radius of first Bohr orbit in hydrogen atom is $$r_{0}$$ then the radius of first orbit in helium atom will be
  • $$2r_{0}$$
  • $$4r_{0}$$
  • $$\dfrac{r_{0}}{2}$$
  • $$r_{0}$$
Cathode rays have velocities
  • Equal to that of light
  • Greater than that of light
  • Less than that of light
  • Greater than that of matter waves
The radius of the first Bohr orbit in hydrogen atom is $$r_0$$ then the radius of first orbit in helium atom will be
  • $$2r_0$$
  • $$4r_0$$
  • $$\displaystyle \frac {r_0}{2}$$
  • $$r_0$$
In a Rutherford scattering experiment when a projectile of charge $$Z_1$$ and mass $$M_1$$ approaches a target nucleus of charge $$Z_2$$ and mass $$M_2$$, the distance of closest approach is $$r_0$$. The energy of the projectile is :

  • Directly proportional to mass $$M_1$$
  • Directly proportional to $$M_1\times M_2$$
  • Directly proportional to $$Z_1Z_2$$
  • Inversely proportional to $$Z_1$$
The number of different wavelengths that is possible to be observed in the spectrum from a hydrogen sample if the atoms are excited to third excited state is:
  • $$3$$
  • $$4$$
  • $$5$$
  • $$6$$
Photon is a
  • Fermion
  • Boson
  • Nucleon
  • Baryon
Radius of first Bohr orbit is $$\ r$$. The radius of 2nd Bohr orbit is 
  • $$8\ r$$
  • $$2\ r$$
  • $$4\ r$$
  • $$\ 2\sqrt{2}r$$
The presence of nucleus in an atom is determined by Rutherford $$\alpha - ray$$ scattering experiment.
  • True
  • False
Why is the screen of the cathode ray tube coated ? Name the material used for coating.
  •  florocent material. 
  • normal material
  • highy resistive material
  • none of these
State the approximate voltage V$$_1$$ used to heat the filament in a cathode ray tube.
  • 6 V
  • 1 V
  • 1000 V
  • 6000 V
In which of the following systems will the radius of the first orbit $$(n=1)$$ be minimum?
  • Doubly ionized lithium
  • Singly ionized helium
  • Deuterium atom
  • Hydrogen atom
What is the purpose of filament in electron gun inside a cathode ray tube?
  • To support the cathode
  • To protect the cathode
  • To cool the cathode
  • To heat the cathode
In a cathode ray tube, what is the effect on the beam of particles if it passes through the electric field?
  • the beam will get deflected towards the cathode
  • the beam will get deflected towards the anode
  • the beam will go undeflected.
  • None of the above
The purpose of cathode in cathode ray tube is ______
  • To emit the electrons
  • To absorb the electrons
  • To deflect the electrons
  • To emit the protons
Name a device which is commonly used to convert an electric signal into a visual signal
  • Cathode ray tube
  • Transducer
  • RMS converter
  • None of the above
State the amount of charge on each particle in a cathode ray tube
  • $$-3.2 \times 10^{-19} C$$
  • $$-1.6 \times 10^{-19} C$$
  • $$+1.6 \times 10^{-19} C$$
  • $$+3.2 \times 10^{-19} C$$
What is the purpose of anode in a Cathode ray tube?
  • To provide potential energy to electrons
  • To provide kinetic energy to protons
  • To provide potential energy to protons
  • To provide kinetic energy to electrons
Name a device which is commonly used to convert an electric signal into a visual signal.
  • Polariser
  • RMS converter
  • Cathode ray tube
  • None of the above
What change is noticed  in cathode ray tube when  the anode voltage is increased ?
  • Brightness of the screen increases.
  • Kinetic energy of electrons reaching the screen increases.
  • Kinetic energy of electrons reaching the screen decreases.
  • Kinetic energy of electrons reaching the screen remains the same.
The diagram below shows a cathode ray tube in which the arrow indicates a beam of charged particles approaching an electric field between the plates A and B. Name the charged particles.
181218_2a5bc1ab407a450da0fbc082b0b53eb3.png
  • Electron
  • Proton
  • Neutron
  • Alpha
Why hotter filament is used in cathode ray tube ?
  • To reduce rate of  electron emission
  • To increases rate of  electron emission 
  • To increases energy  emission
  • To decrease energy  emission 
Which one of the following properties is not found in cathode rays ?
  • Cathode rays can produce x-rays
  • The properties of cathode rays differ from the properties of x-rays
  • The cathode rays possess too much kinetic energy
  • Cathode rays are not deflected by electric and magnetic field
How does mass change with increase in temperature?
  • Unchanged
  • Increases
  • Decreases
  • Can't say
If the pressure within a discharge tube is reduced from $${10}^{-3}   mm$$ to $${10}^{-4}  mm$$ mercury then the rays which are produced perpendicular to the cathode surface are known as
  • Anode rays
  • Cathode rays
  • X-rays
  • Canal rays
The conditions for the discharge of electricity in a discharge tube are :
  • high temperature and high potential
  • low pressure and high potential
  • low pressure and high temperature
  • low potential and high pressure
The idea of parmanu was given by :
  • Maharishi Kanad
  • Democritus
  • Dalton
  • William Crookes
The name atom belongs to which language ?
  • Latin
  • English
  • French
  • Greek
The lamp whose working is based on a discharge tube is ________ .
  • Fluorescent lamp
  • Incandescent lamp
  • CFL
  • Both (A) and (C)
The fluorescence of the glass (discharge) tube at very low pressure is characteristic of ________ .
  • the phosphors in the material of the glass
  • the gas used in the tube
  • the cathode
  • all the above
Complete the following :
Mass $$=$$___________  $$ \times $$ density
  • Volume
  • Area
  • Width
  • Density
A modified discharge tube is used as a ________ .
  • cathode ray oscilloscope
  • fluorescent tube
  • x-ray tube
  • all the above
In a vacuum diode, the space around the cathode which is filled with electrons, is called ________ .
  • space charge
  • electric field
  • magnetic field
  • electron cloud
Who discovered the positively charged particle called proton?
  • Chadwick
  • Goldstein
  • Rutherford
  • None of these
An element has number of proton =Then what will be its atomic number?
  • 9
  • 7
  • 16
  • 2
The positively charged center in an atom is called as:
  • nucleus
  • neutron
  • proton
  • electron
Ernest Rutherford carried out his work on discovery of nucleus with:
  • silver foil experiment
  • gold foil experiment
  • $$\displaystyle \beta -$$ particle experiment
  • None of the above
Who is known as the father of nuclear physics?
  • Ernest Rutherford
  • Dalton
  • J.J. Thomson
  • E. Goldstein
Which of the following was carried out by Rutherford in his experiment?
  • Fast moving alpha-particles were made to fall on a thin silver foil.
  • Fast moving beta-particles were made to fall on a thin gold foil.
  • Fast moving alpha-particles were made to fall on a thin gold foil.
  • Fast moving gamma-particles were made to fall on a thin gold foil.
An element has number of electrons  =Then what will be its atomic number?.
  • 1
  • 4
  • 3
  • 2
0:0:1


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