PUNJAB Academy CHINIOT
Paper for Entry Test Preparation
Physics 2nd year Chapter No. 20
Total marks:- 120 Time
allowed 20 minutes
Note:- Fill
the appropriate answer of the following questions in the answer sheet. Double
filling and erasing is not allowed. Each question carries equal marks and for
each wrong answer minus one is awarded.
1) The
first series which was identified in the spectrum of hydrogen is called:
a) Lyman series b) Balmer series c) Paschan series d) Pfund series
2) Balmer
series lies in that region of electromagnetic wave spectrum which is called:
a) Visible b) Invisible c) Infrared d) Ultraviolet
3) The
results of spectra obtained by Balmer were ecpressed in 1896 by:
a) Bohr b) Rydberg c) Planck d) Rutherford
4)
Spectrum represents the number of component colours present in certain light in
terms of:
a) Wavelength b) Frequency c) Energy d) All of above
5) The
series that lies in the infra red region:
a) Pfund series b) Brackett series c) Paschan series d) All of these
6)
Lyman series in the spectrum if hydrogen exists in the:
a) Infrared region b) Visible region c) Ultraviolet region d) Both (a) and (b)
7)
The spectrum emitted from hydrogen filled discharge tube is:
a) Line spectrum b) Discrete spectrum c) And spectrum d) Absorption spectrum
8) The
formula of bracket series can be obtained by putting in the general formula,
the value of n equal to:
a) One b) Two c) Three d) Four
9)
An electron of the hydrogen atom in the second orbit is called its:
a) Ground state b Excited state c) Ionized state d) Non of all
10)
mvr is an expression for:
a) Linear momentum b) Angular momentum c) Momentum of a force d) Torque
11)
Whenever an electron makes a transition
a) A photon of energy hf is
absorbed b)
A photon of energy hf is emitted
c) Either (a) or (b) d)
An electron is emitted
12)
Normally the electron of the hydrogen atom is in the energy state which is:
a) Designated as n = 1 b) Called ground state c) Called normal state d) Both (b) and (c)
13)
By notation, the distance of nth orbit from the nucleus is:
a) Larger as compared to that of
pth orbit b)
Smaller as compared to that of pth orbit
c) Much smaller as that of pth
orbit d)
Any of these
14)
The value of Eo / hc comes out to be equal to the value of:
a) Rydberg constant b) Planck’s constant c) Wein’s constant d)
Stefen’s constant
15)
Energy required by an electron revolving in certain orbit to jump to an excited
state is called:
a) Ionization energy b) Ionization potential c) Excitation energy d)
Excitation potential
16)
X-rays are:
a) Mechanical waves b) Longitudinal waves c) Electromagnetic waves d) Both (a) and (b)
17)
The study of characteristic X-rays spectra has played an important role in the
study of:
a) Atomic spectra of elements b)
Periodic table of elements
c) Both (a) and (b) d)
Malleability of elements
18)
The anode used in the X-ray tube is usually made of:
a) Beryllium b) Carbon c) Tungsten d) Copper
19)
X-rays photons are:
a) More energetic than γ-rays b) Less
energetic than visible light
c) Less energetic than γ-rays d) Less
energetic than infrared light
20)
Kβ X-rays are actually:
a) Positrons b) Protons c) Photons d) Electrons of
high energy
21)
Characteristics X-rays are so called because:
a) Their masses are absolute b)
Their energies cannot be predicted
c) Their energies depends upon
the type of target material d) Their
charge is zero
22)
The characteristics X-rays appear as:
a) Continuous spectrum b)
Discrete line on continuous spectrum
c) Band spectrum d)
Discrere spectrum
23)
X-rays penetrate in a solid matter through a distance of several:
a) Kilometer b) Meters c) Centimeter d) A few angstroms
24)
As compared to bones, the flesh:
a) Contain greater proportion of
light elements b)
Allows greater amount of X-rays to pass through
c) Both (a) and (b) d)
Absorb greater amount of incident X-rays
25)
Characteristics X-rays are produced:
a) From light elements b) From heavy elements c) Due to inner shell transitions d) Both (a) and (c)
26)
Lasers are used to produces a beam of visible light which is:
a) Intense b)
Monochromatic c)
Multidirectional d) Both
(a) and (b)
27)
A metastable state:
a) Is an excited state b)
Is that in which excited electron is stable
c) Is that in which excited
electron is usually instable d)
Non of all
28)
The lasing or active medium in He-Ne laser discharge tube is:
a) Nitrogen b) Helium c) Hydrogen d) Neon
29)
As compared to other excited states, the transition from or to metastable state
is comparatively:
a) Easy b) Difficult c) Too common d) Impossible
30)
In the production of laser beam, for each incident photon, we will have two
photons going:
a) In the same direction b)
In opposite directions
c) In arbitrary directions d)
At right angles to each other
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