Specimen Question Paper Physics : ISC +2 12th Std Plus Two www.cisce.org

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Document Described : Physics Question Paper, ISC Question Paper

PHYSICS
PAPER – 1
(THEORY)
(Three hours)
(Candidates are allowed additional 15 minutes for only reading the paper.
They must NOT start writing during this time.)
Answer all questions in Part I and six questions from Part II, choosing two questions from each of the Sections A, B and C.
All working, including rough work, should be done on the same sheet as, and adjacent to, the rest of the answer.
The intended marks for questions or parts of questions are given in brackets [ ].
(Material to be supplied: Log tables including Trigonometric functions)
A list of useful physical constants is given at the end of this paper.

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http://www.cisce.org/ISC%202013%20Sp...QP/Physics.pdf

PART I (20 Marks)
Answer all questions.
Question 1
Choose the correct alternative (a), (b), (c) or (d) for each of the questions given below: [5]
(i) Two point charges 17.7 µC and -17.7µC, separated by a very small distance, are kept inside a large hollow metallic sphere. Electric flux emanating through the sphere is:
(a) 2 ×106 Vm
(b) -2 ×106 Vm
(c) Zero
(d) 4 ×106 Vm
(ii) Ohm’s Law, in vector form is:
(iii) If the current (I) flowing through a circular coil, its radius (R) and number of turns
(N) in it are each doubled, magnetic flux density at its centre becomes:
(a) Two times
(b) Four times
(c) Eight times
(d) Sixteen times
(v) Ratio of the radius of third Bohr orbit to the radius of second Bohr orbit in hydrogen atom is:
(a) 2:3
(b) 4:9
(c) 9:4
(d) 3:2
B. Answer all questions given below briefly and to the point: [15]
(i) A dielectric slab of relative premittivity (i.e. dielectric constant ) 6 is introduced between the two plates of an 8µF air capacitor, in order to completely occupy the space between the two plates. Find the new capacitance of the capacitor.
(iii) Current ‘I’ flowing through a metallic wire of area of cross-section ‘a’ is given by the equation I = naevd. What is the meaning of the symbols ‘n’ and ‘vd’?
(iv) State two conditions which must be satisfied in order ito apply Tangent law in magnetism.
(v) A metallic wire carrying a current is kept in a uniform magnetic field, at different angles. At what angle, is the force acting on it maximum?
(vi) What type of wave front is associated with a line source of light?
(vii) Calculate the polarizing angle for glass whose refractive index is 1.6.
(viii) What is the optical power in dioptre of a concave lens of focal length 50 cm?
(ix) What is meant by ‘resolving power’ of a telescope?
(x) How can the defect of short sightedness be corrected?
(xi) Out of the following, which one cannot be the charge of a body?
+8.0×10-19C, -3.2×10-19C, 2.4×10-19C, or 6.4×10-19C
(xii) Name the series of lines in the hydrogen spectrum which lies in the infrared region.
(xiii) Explain the statement: “Half life of Polonium is 3.8 days.”
(xiv) How much matter has to be destroyed to create 9×1013J of energy?
(xv) In Semi-Conductor Physics, what is LED?

PART II (50 Marks)
Answer six questions in this part, choosing two questions
from each of the Sections A, B and C.

SECTION A
Answer any two questions.
Question 3
(a) Draw a labelled diagram of a potentiometer circuit used to measure internal resistance of a cell. In this experiment, what is the expression for the internal resistance ‘r’? [3]
Question 4
(b) Define ‘time constant’ of an LR circuit. What is its MKS unit? [2]
(c) (i) In the circuit shown in Figure 5 below, calculate phase difference between the current and the supply voltage: [4]
(ii) What is meant by the term band width of an LCR circuit?

SECTION B
Answer any two questions
Question 5
(a) With reference to radio wave communication, explain the terms: [2]
(i) Amplitude modulation
(ii) Frequency modulation
(b) In Young’s double slit experiment, using light of wavelength 600 nm, 10th bright fringe is obtained on a screen, 3mm from the centre of the pattern. If the screen is 120 cms away from the slits, calculate: [3]
(i) Distance between the two slits
(ii) Fringe width, i.e. fringe separation.
(c) What is meant by diffraction of light? What is an optical grating? State its use. [3]

Question 7
(a) A narrow and parallel beam of white light is incident on a convex lens, parallel to its principal axis. Draw a labelleld diagram to show how coloured images are formed by the lens. [2]
(b) Find the distance between the two lenses of a Compound Microscope if the final image formed by the microscope is virtual and lies at a distance of 25 cm to the left of the eye-piece. Magnifying power of the microscope is 30 and focal lengths of objective and eyepiece are 2cm and 5cm, respectively. [4]
(c) You are provided with two convex lenses having focal lengths 4 cm and 80 cm, respectively, to form an astronomical telescope. [2]
(i) Which lens would you use as an objective of an astronomical telescope and which one as an eyepiece?
(ii) If the telescope is in normal adjustment, what is its:
(1) Magnifying power?
(i) Find the minimum wavgelength of the X rays emitted by the X ray tube.
(ii) What will be the effect of replacing the 6 V battery by a 9 V battery on the emitted X rays?
(b) What is meant by mass defect of a nucleus? How is it related to its binding energy? [2]
(a) An electron is passed through a potential difference of 400 V. [3]
(i) Calculate the speed acquired by the electron.
(ii) If it enters a transverse and uniform magnetic field, what is the nature of the path described by the electron?
(b) (i) Explain the statement: “Work function of a certain metal is 2.0 eV.” [3]
(ii) Calculate the maximum wavelength of electro-magnetic radiation which will cause photo emission from this metal.

Question 10
(b) Draw a labelled circuit diagram of an arrangement used to study characteristic curves of a P'P or an 'P' transistor in common emitter mode. [3]
(c) What is the symbol of a 'A'D gate? Write its truth table. [2]
Useful Constants and Relations:
1. Planck’s constant (h) = 6.6 × 10-34 Js
2. Speed of Light in vacuum (c) = 3.0 × 108 ms
3. Charge of an electron (-e) = 1.6 × 10-19 C

PHYSICS
PAPER – 2
(PRACTICAL)
(Three hours)
(Candidates are allowed additional 15 minutes for only reading the paper.
They must (OT start writing during this time.)
ALL A'SWERS MUST BE WRITTE' I' THE A'SWER BOOKLET
PROVIDED SEPARATELY.
If squared paper is used, it must be attached to the answer booklet.
Marks are given for a clear record of observations actually made, for their suitability and accuracy, and for the use made of them.
A brief statement of the method may be given if necessary. The theory of the experiment is not required unless specifically asked for.
Candidates are advised to record their observations as soon as they have been made.
All working, including rough work, should be done on the same sheet as, and adjacent to, the rest of the answer.
Mathematical tables and squared paper are provided. The intended marks for questions or parts of questions are given in brackets [ ].
Answer all questions.
You should not spend more than one and a half hours on Question 1.

Question 1 [10]
This experiment determines the focal length of a convex lens by the displacement method.
Determine the approximate focal length f of the given convex lens (marked M) by projecting the image of a distant object on a wall or a screen. Record the value of f in cm.
Adjust the distance x between O and I to be equal to 70 cm. Ensure that this separation is maintained throughout this particular set up.
Move the convex lens towards the pin I and adjust its position until the diminished and inverted image of O coincides with the image pin I. Record the position M1 of the lens on the metre scale. Show this reading to the Visiting Examiner. Calculate the focal length F upto one decimal place, where F = 25 × S.

Question 2 [7]
This experiment determines resistivity of the material of a wire. You are
provided with a 1 m long uniform wire AB stretched along a metre scale and provided with binding terminals at the two ends. You are also provided with a resistance box RB, a piece of wire ‘P’ wound on a wooden bobbin and provided with binding terminals, a jockey ‘J’, a 2 V d.c. power supply (E), a plug key ‘K’, a centre-zero galvanometer ‘G’ and a few connecting wires. Now set up the circuit as shown in Figure 2 below. Ensure that all connections are tight.

Question 3 [3]
Find the least count of the given micro meter screw gauge. Using it, determine the diameter ‘D’ of the sample wire ‘W’. Record its value in your answer book in mm. Show your reading of the screw gauge to the visiting examiner. Then find the radius r of the wire in cm. Using this value of r and the value of Yo of Question 2, find the value of K where:
K = 2 4 10 . o r Y

Question 4
Show the following to the Visiting Examiner for assessment:
(a) Project [7]
(b) Physics Practical File. [3]

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How to solve Question 1-a -1?

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Solutions to sample paper