Download Vacation-Assignment-Science-XII-2073

PENTAGON INTERNATIONAL COLLEGE
TINKUNE, KATHMANDU
Happy Vijaya Dashami, Deepawali, Nepal Sambat–1137 and Chhath–2073
Vacation Assignment
Science –XII
Note:– Students must prepare Dashain Assignment
separate note copy for each Subject.
Chemistry
1. Prepare a term paper on “Discovery of Grignard Reagent By Victor Grignard and its important applications”
including following points:–

History of Discovery of Grignard reagent

Introduction– aliphatic and aromatic Grignard reagent

Preparation and Precautions

About Victor Grignard, Nobel Prize

Applications with reactions

Organometallic Compounds
[At least Five pages]
2. Discuss physical and chemical properties of Benzene, Chlorobenzene and Nitrobenzene.
3. What are Electrophilic and Nucleophilic Substitution reactions? Explain with examples.
4. Prepare a paper on ‘selection of indicator on the basis of PH Titration curves’.
5. Give explanation on ‘Collision Theory of Reaction’ and ‘Transition state (Activated Complex)
Theory’. Specify limitations of Collision Theory also.
6. Practice all numerical problems of Volumetric analysis and Chemical Kinetics from Question Bank.
7. Solve the all questions from 1st term examination–2073 question paper of Chemistry.
8. Discuss metallurgical process for extraction of copper. Also discuss general metallurgical trends.
Mathematics

All worked out examples from the chapters taught from basic mathematics and conceptual Mathematics.

All the HESB questions from Old is Gold of the chapters taught.
Compulsory English

Complete the exercises from workbook of meaning into words upto unit–6.

Write a critical essay focusing on the strength and weakness of your college. Also include your expectation
that you think management should include for the advancement of your studies.
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Biology
Zoology
Long questions
1.
What is tissue? Give an account of various types of Epithelial tissue with well labeled diagrams in context of
their structure, location and functions.
2.
What is Nutrition? Discuss various types of nutrition with examples.
3.
What is Gametogenesis? Explain the process of formation of both male and female gamets with well labeled
diagrams.
Short questions
1.
Difference between the followings.
a) Striated and unstriated muscles b) Blood and Lymph c) Ligaments and tendons d) Bone and cartilage
e) Myelinated and non myelinated nerve fibre
2.
What is blood? Explain composition and structure of human blood.
3.
What is balanced diet? Describe the role of nutrients in human body.
4.
Give an account of structure of alimentary canal of human body with a well labeled diagram.
5.
What is malnutrition? Discuss various disorders due to under–nourished and over–nourished conditions.
Botany
Long questions
1. Describe the internal structure of dicot root.
2. What is osmosis? Explain the process of it with suitable experiment.
3. Describe the structure and function of DNA.
Short questions
1. Difference between the followings.
a) meristem and permanent tissue b) parenchyma and sclerenchyma c) protoxylem and metaxylem d)
Phenotype and genotype e) active and passive absorption of water f) diffusion and osmosis.
4. Describe in a brief: a) structure and function of phloem b) significance of plasmolysis and imbibition c)
significance of vegetative propagation d) significance of variation e) process of micro and megasprogenesis
Physics
Theory Questions
1.
Define wave motion and progressive wave. Derive the progressive wave equation in a medium in terms of wave
vector and displacement.
2.
What is the principle of superposition of waves? Discuss the result of superposition of two waves of equal
amplitude and same frequency travelling in opposite direction.
3.
How is a progressive wave differing from a stationary wave? Use the principle of superposition of two waves to
find the position of displacement of nodes and antinodes in a standing wave.
4.
Write down the Newton’s formula for the velocity of sound in air. Explain why this formula has to be modified.
Discuss Laplace’s correction on it.
5.
Discuss the significance of Laplace’s correction to Newton’s formula for the velocity of sound. Also explain how
different factors affect the velocity of sound.
6.
Derive the expression of the velocity of sound in a medium by dimension method. Write down the factors on
which velocity of sound in air depends with necessary explanation.
7.
Distinguish between harmonics and overtones. Derive an expression for the n th overtone of an open organ pipe.
8.
What is organ pipe? Describe the various mode of the air column in a closed organ pipe.
9.
Prove, with necessary diagrams, that both types of harmonics odd and even can be produced in an organ pipe
open at both ends.
10. State and explain Huygens’s principle. Derive the law of reflection on the basis of this principle.
11. State and use Huygens’s principle of wave theory to verify the laws of refraction of light.
12. Describe Foucault’s method for the determination of velocity of the light.
13. Describe Michelson’s method for the determination of velocity of the light. Write advantages of this method over
Foucault’s method.
11. Describe the mechanism of metallic conduction and define drift velocity of electrons. Establish a relation
between drift velocity of electrons and current density in the conductor.
12. State and explain Ohm’s law. How would you verify it experimentally?
13. Distinguish between the resistance and resistivity. Derive the expressions of effective resistance of number of
resistances connected in series and parallel.
14. State and explain Biot – Savart law. Use this law to find the magnetic field due to a long straight current carrying
conductor.
15. State Biot – Savart law. Derive an expression for the magnetic field produced by a current carrying circular coil
at any point on the axis of circular coil.
16. Deduce an expression for the magnetic field at a point along the axis of a solenoid and at the midpoint of the
solenoid by using Biot – Savart law.
17. Find the expression of the force experienced by a moving charge in a magnetic field. Discuss the cases when
the force is minimum and maximum. Define the magnetic field in term of force on a moving charge.
18. Define an expression for the force experienced by a conductor carrying current when placed in a uniform
magnetic field.20
19. Describer with the necessary theory the effect of the electric field on an electron moving perpendicular to the
field direction.
20. Show that the electron motion in magnetic field is circular. Prove that frequency and time period are
independent with the velocity of the electron.
21. Describe with necessary theory J. J. Thomson’s method to determine the specific charge of an electron.
22. Describe with necessary theory of Millikan’s oil drop experiment to determine the value of the charge associated
with an electron.
23. Describe the phenomenon of electric discharge through gases.
24. What are the cathode rays? How are they produced? Mention their important properties.
25. Define photoelectric effect. Derive Einstein’s photoelectric equation. Define the various terms used in it.
26. Describe with necessary theory, the Millikan’s experiment for the verification of Einstein’s photoelectric equation
and determination of the Planck’s constant.
27. State Bohr’s postulates of hydrogen atom. Use them to calculate the radius and velocity of n th orbit of the
hydrogen atom.
28. State Bohr’s postulates of hydrogen atom. Use them to determine the total energy of an electron in the nth orbit
of the hydrogen atom.
29. Discuss the Bohr’s Interpretation of the hydrogen spectrum and explain the various spectral series of hydrogen
atom by using energy level diagram.
30. What do you mean by wave particle duality of light? State the de Broglie hypothesis. Derive an expression of
wavelength associated with matter wave. Can you realize this wave in daily life?
31. State and Explain Heisenberg’s uncertainty principle in terms of position and linear momentum of a particle. Use
this principle to show that the electron is not constituent of the nucleus.
32. State and Explain Heisenberg’s uncertainty principle. Use this principle to show that the proton exists inside the
nucleus.
33. What is laser? Describe construction, working principle and working of He–Ne laser. Write its some uses.
Numerical Questions
1.
If the velocity of sound in air is 340 m/s, calculate (i) the wavelength when the frequency is 256 Hz, (ii) the
frequency when the wavelength is 0.85 m.
2.
Write the equation for a progressive wave moving along the positive X–axis with the following data: amplitude
(a) = 0.004 m, time Period (T) = 0.5 sec and wavelength (λ) = 0.5 m
3.
A progressive wave is represented by y=2sin (20𝜋t – 31.4x), where x and y are in meters. Calculate the
amplitude, frequency, wavelength and the velocity of the wave.
4.
An open organ pipe is turned to a frequency of 440 Hz when the temp is 27 0C. Find its frequency when the
temperature drops to 0 0C.
5.
Calculate the bulk modulus of a liquid in which longitudinal wave with a frequency of 250 Hz has the wavelength
of 8 m if the density of the liquid is 900 kgm–3.
6.
A man standing at one end of a closed corridor 57 m long blow a short blast on a whistle. He found that the time
from the blast to the sixth echo was 2 s. If the temperature was 17 0C what was the velocity of sound at 0 0C.
7.
The interval between the flash of lighting and the sound of thunder is 2 s, when the temperature is 10 0C. How
far is the storm if the velocity of the sound in air at 0 0C is 330m/s.
8.
At what temperature the velocity of sound in air is increased by 50% to that at 27 0C.
9.
The radius of curvature of the curved mirror is 20 meters and the plane mirror is rotated a 20 revs –1,calculate the
angle in degrees between a ray incident on the plane mirror and then reflected from it after the light has traveled
to the curved mirror and back to the plane mirror (velocity of light = 3 x 10 8 ms–1).
10. A horizontal beam of light is reflected by a vertical plane mirror A, travels a distance of 250 meters, is then
reflected back along the same path and is finally reflected again by the mirror A. When A is rotated with
constant angular velocity about a vertical axis in its plane, the emergent beam is deviated through an angle of
18 minutes. Calculate the number of revolutions per second made by the mirror. (c=3 x 10 8 m/s)
11. A thin film resister in a solid state circuit has a thickness of 1 μm and made of nichrome of resistivity 10 –6 ohm
meter. Calculate the resistance available between opposite edges of a 1 mm 2 area of film (a) if it is square
shaped, (b) if it is rectangular, 20 times as long as it is wide.
12. A strip of metal 1.2 cm wide and 1.5 x 10 –3 cm thick carries a current of 0.50 A along its length. If it is assumed
that the metal contains 5 x 1022 free electrons per cm3, calculate the mean drift velocity of these electrons
(e=1.6x10–19 C).
13. A tungsten coil has a resistance of 12.0 Ω at 15 0 C. If the temperature coefficient of resistance of tungsten is
0.004 K–1, calculate the coil resistance at 180 C.
14. A nichrome coil has a resistance 4.08 Ω at 500 C and 4.016 Ω at 100 C. What will be its resistance at 250 C?
15. What is the magnetic flux density at the centre of a circular coil of 100 turns and radius 2.5 cm carrying a current
of 10 A?
16. A horizontal wire of length 5 cm and carrying a current of 2 A is placed in the middle of a long solenoid at right
angles to its axis. The solenoid has 1000 turns per meter and carries a steady current I. Calculate I if the force
on the wire is vertically downwards and equal to 10–4 N.
17. A circular coil has 100 turns and a mean diameter of 20 cm. It carries a current of 5 A. Find the strength of the
magnetic field at a point on its axis at a distance of 15 cm from the center of the coil.
18. A copper wire 14 m long is wound into a flat circular coil 4 cm in diameter. If an electric current of 9 A flows
through the coil, what is the flux density at the center of the coil?
19. A copper wire has 1.0 x 1029 free electrons per cubic meter, a cross sectional area of 2.0 mm 2 and carries a
current of 5.0 A. Calculate the force acting on each electron if the wire is now placed in a magnetic field of flux
density 0.15 T which is perpendicular to the wire. (e= –1.6x10–19 c)
20. A beam of electrons moving with a velocity of 4 x 107 m/s enters mid–way between two horizontal plates in a
direction parallel to the plates. The plates are 4 cm long and 2 cm apart and have a P.d. 200 V applied between
them. What is the vertical deflection of the beam as it emerges from the plates? [e/m =1.8 x 1011 CKg–1]
21. An electron with a velocity of 107 m/s enters a region of uniform magnetic flux density of 0.10 T, the angle
between the direction of the field and initial path of the electron being 35 0. Find the axial distance between two
turns of the helical paths. (e/m=1.76x1011 CKg–1)
22. A beam of protons is accelerated from rest through a potential difference of 2000V and then enters a uniform
magnetic field which is perpendicular to the direction of the proton beam of the flux density 0.2 T. Calculate the
radius of the path which the beam describes.[proton mass=1.7x10 –27 kg. Electron charge =–1.6x10–19 C]
23. An oil drop of mass 3.25x10–15 kg falls vertically with uniform velocity, through the air between vertical parallel
plates which are 2 cm apart. When a p.d. of 1000 V is applied to the plates the drop moves to the negatively
charged plate, its path being inclined at 450 to the vertical. Calculate the charge on the drop.
24. In a Millikan–type apparatus the horizontal plates are 1.5 cm apart. With electric field switched off an oil drop is
observed to fall with steady velocity 2.5 ×10 –2 cms–1.When the field is switched on the upper plate being
positive, the drop just remains stationary when the potential difference between the plates is 1500V.Calculate
the radius of the drop and the number of electronic charges. (Given: density of oil =900 Kg m –3 and viscosity of
air =1.8 × 10–5Nsm–2, Neglect air density)
25. An electron of energy 20 eV comes into collision with a hydrogen atom in its ground state. The atom is excited
into a state of higher internal energy and the electron is scattered with reduced velocity. The electron
subsequently returns to its ground state with emission of a photon of wavelength1.21 x 10 –7 m. Determine the
velocity of scattered electron.
26. If the wavelength of the incident light is reduced from 400 nm to 360 nm, there is a change in the stopping
potential of 0.34V. Find the value of Planck constant.
27. The photoelectric work function of potassium is 2 eV and the surface is illuminated with radiation of wavelength
350 nm. What potential difference has to be applied between a potassium surface and the collecting electrode
in order just to prevent collection of electron? What would be the kinetic energy of the electrons?
28. If 10% of the energy supplied to an incandescent light bulb is radiated as visible light, how many visible quanta
are emitted per second by 100W bulb? Assume the wavelength of all the visible light to be 560 nm.
29. Electrons with maximum kinetic energy of 3 eV are ejected from metal surface by ultra–violet radiation of
wavelength 1500A0.Determine work function, threshold wavelength and the stopping potential.
30. The ground state of the electron in the hydrogen atom may be represented by the energy –13.6 eV and the first
two excited states –3.4 eV and –1.5 eV respectively. On a scale in which an electron completely free of the
atom is at zero energy. Use this data to calculate the ionization potential of the hydrogen atom and the
wavelength of three lines in the emission spectrum of hydrogen. (Charge of electron =1.6x10 –19 C, speed of light
in vacuum =3.0x108 m/s, the plank constant =6.6x10–34 Js)
31. Find the wavelength of radiation emitted from a hydrogen atom when an electron jumps from third orbit to
second orbit. (Given:∈0 =8.854 × 10–12 c2N–1m–2, h=6.62x10–34 Js, me=9.1x10–31 kg)
32. In the singly ionized helium atom, a single electron orbits the nucleus which has a charge of 2e. What is the
radius of the first Bohr’s orbit for this ion? (∈0 =8.85x10–12 F/m, h=6.62x10–34Js, me= 9.1x10–31 kg, e=1.6x10–19 C)
33. Find De–Broglie’s wavelength of an electron accelerated through a potential of 30 volt. (mass of electron me=
9.1x10–31 kg, e=1.6x10–19 C)
34. An electron has a speed of 300 m/s accurate to 0.01%. With what fundamental accuracy can we locate the
position of the electron? (h=6.62x10–34 Js, m= 9.1x10–31 kg)
35. A radar pulse lasts for 0.25 micro–second. What is the order of uncertainty in the energy of photons?
Date of submission on 29 Kartik, 2073.