XII Standard - 12th - Chemistry - Second Midterm Test Question Paper - Samacheer Kalvi
II-MID
TERM TEST
CLASS: XII TOTAL MARKS: 50
SUBJECT: PHYSICS
TIME: 2 hrs
PART-1
Choose the most appropriate answer
from the given four alternatives and write the option code and the
corresponding answer. 1x10=10
1.
The transverse nature of light is shown in,
(a) interference (b) diffraction (c) scattering (d) polarisation
2.
Two coherent monochromatic light beams of intensities I and 4I are
superposed. The maximum and minimum possible intensities in the
resulting beam are
(a) 5I and I (b) 5I and 3I (c) 9I and I (d) 9I and 3I
3.
Two radiations with photon energies 0.9 eV and 3.3 eV respectively are falling
on a metallic surface successively. If the
work function of the metal is 0.6 eV,
then the ratio of maximum speeds of emitted
electrons in the two cases will be
(a) 1:4 (b) 1:3
(c) 1:1 (d)1:9
4.
If the mean wavelength of light from sun is taken as 550 nm and its mean
power as 3.8 × 1026 W, then the
number of photons emitted per second from the
sun is of the order of
a) 1045 b) 1042 c) 1054 d) 1051
5.
Light of frequency 1.5 times the threshold frequency is incident on a
photosensitive material. What will be the
photoelectric current if the frequency
is halved and intensity is doubled?
a) one-fourth b) zero
c) doubled d) four times
6.
The half-life period of a radioactive element A is same as the mean life time
of
another radioactive element B. Initially
both have the same number of atoms.
Then
(a) A and B have the same decay rateinitially
(b) A and B decay at the same rate
always
(c) B will decay at faster rate than A
(d) A will decay at faster rate than B.
7.
In a hydrogen atom, the electron revolving in second orbit, has angular
momentum equal to
a) 
b)
c) 
d) )
8.
Emission of electrons by the absorption of heat energy is called………emission.
a)
photoelectric b) field c) thermionic d) secondary
9. First diffraction minimum due to a single
slit of width 1.0×10–5 cm is at
30o. Then wavelength of light used is,
(a) 400 Å (b) 500 Å (c) 600 Å
(d) 700 Å
10. An example of uniaxial crystal is
a) selenite b) Mica c) Topaz
d) calcite
PART-II
Note : Answer any FIVE questions. Question
No. 14 is compulsory. 5x2=10
11.
State Huygen’s principle
12.
A proton and an electron have same kinetic energy. Which one has greater
de Broglie wavelength? Justify.
13.
Define impact parameter.
14.
The radius of the 5th orbit of hydrogen atom is 13.25 Å. Calculate the de
broglie wavelength of the electron
orbitting in the 5th orbit.
15.
Define work function of a metal. Give its unit.
16.
Differentiate: Interference and Diffraction
17.
Calculate the cut-off wavelength and cutoff
frequency of x-rays from an x –ray
tube
of accelerating potential 20,000 V.
PART-III
Note : Answer any five questions. Question
No. 22 is compulsory. 5x3=15
18.
Prove law of reflection using Huygens’ principle.
19.
Give the construction and working of photo emissive cell.
20.
Derive an expression for de Broglie wavelength of electrons.
21.
Discuss the spectral series of hydrogen atom.
22.
Calculate the amount of energy released when 1 kg of 92U235undergoes
fission
reaction.
23.
Differentiate between Fresnel and Fraunhofer diffraction
24.
Two light sources with amplitudes 5 units and 3 units respectively interfere
with each other. Calculate the ratio of
maximum and minimum intensities.
PART-IV
Note : Answer all the questions.
5x3=15
25.
Discuss about the simple microscope and obtain the equations for
magnification for near point focusing and
normal focusing.
(OR)
Obtain the equation for bandwidth in
Young’s double slit experiment.
26.
Obtain Einstein’s photoelectric equation
with necessary explanation.
(OR)
Describe briefly Davisson – Germer experiment
which demonstrated the
wave nature of electrons.
27.
Explain the J.J. Thomson experiment to determine the specific charge of
electron.
(OR)
Derive the expression for radius of nth
orbit of hydrogen atom using
Bohr atom model
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