THE INDIAN COMMUNITY SCHOOL, KUWAIT SERIES : I SE / 2016-2017 CODE : N 042 MAX. MARKS : 70 TIME ALLOWED : 3 HOURS NO. OF PAGES : 6 PHYSICS ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ General Instructions a) All questions are compulsory. b) There are 26 questions in total. Questions 1 to 5 carry one (1) mark each, questions 6 to 10 carry two (2) marks each, questions 11 to 22 carry three (3) marks each, question 23 carry four (4) marks and questions 24 to 26 carry five (5) marks each. c) Use of calculator is not permitted. d) You may use the following physical constants wherever necessary. e = 1.6 X 10-19 C c = 3 X 10 8 m/s h = 6.6 X 10-34 JS µ 0 = 4π X 10-7 TmA -1 I. Very short answer questions 5 X 1 = 5 Marks 1. In which orientation a dipole placed in a uniform electric field is in:- a. Stable b. Unstable Equilibrium 2. The susceptibility of magnetic material is 1.9 X 10-5. Nam e the type of magnetic material it represents. 3. How does mutual inductance of a pair of coils changes when; a. Distance between the coils is increased. b. Number of turns in the coils is increased. 4. Two wires equal length, one of copper and other of Magnanin have the same resistance, which wire is thicker? 5. At what angle of incidence should a light beam strike a glass slab of refractive index 3 such that the reflected and refracted rays are perpendicular to each other? II. Short answer questions (Type-1) 5 X 2 = 10 Marks 6. A battery of EMF 10V and internal resistance 3Ω is connected to a resistor. If the current in the circuit is 5A calculate the following: - a. The resistance of the resistor. b. The terminal voltage of the battery. 7. Explain giving reasons the basic difference in converting a galvanometer into: - a. Voltmeter b. Ammeter
8. An AC voltage of 100V, 50Hz is connected across a 20Ω resistor and 2mH inductance in series. Calculate the following in the circuit: - a. Impedance b. RMS current Predict the direction s of induced currents in metal rings 1 and 2 lying in the same plane where current I in the wire is increasing steadily. 9. Why infrared radiations are referred to as heat waves also? Name the radiation next to it on electromagnetic spectrum having: - a. Shorter wavelength b. Longer wavelength 10. A convex lens of focal length 25cm is placed coaxially in contact with a concave lens of focal length 20cm. Determine the power of the combination. Will the system be converging or diverging? III. Short answer questions (Type-2) 12 X 3 = 36 Marks 11. Find the amount of work done in arranging the three point charges, on the vertices of an equilateral triangle ABC, of side 10cm, as show in figure. A charge q is placed at the center of the line joining two equal charges Q. Show that the system of three charges will be in equilibrium if q = -Q/4. 12. Derive the expression for the stored in a parallel plate capacitor with air between the plates. How does the stored energy change if air is replaced by a medium of dielectric constant K?
13. Define the term current density of a metallic conductor. Deduce the relation connecting current density (J) and the conductivity σ of the conductor, when an electric field E, is applied to it. 14. Figure below shows experimental set up of a meter bridge. When the two unknown resistances X and Y are inserted, the null point D is obtained 40cm from the end A. When a resistance of 10Ω is connected in series with X, the null point shifted by 10cm. Find the position of the null point when the 10Ω resistance instead of connecting with resistance X is connected in series with resistance Y. Determine the values of resistances X and Y. 15. Two long parallel conductors A and B separated by a distance d carry steady currents i A and i B respectively. Show by using Biot-Savart law and the Lorentz force that the magnitude of the force on a segment L of conductor B due to A is given by; F BA =µ 0 i A i B L/2πd 16. How do the paramagnetic and diamagnetic materials, when placed in an external magnetic field, behave? Sketch the magnetic field lines in both the cases and distinguishing between these in terms of magnetic susceptibility. 17. Draw the field lines of: - a. Bar magnet b. Current carrying finite solenoid c. Electric dipole 18. A. State Faraday s law of electromagnetic induction. B. A jet plane is travelling towards west at a speed of 1800km/h. What is the voltage difference developed between the ends of the wing having a span of 25m, if the Earth s magnetic field at the location has a magnitude of 5 X 10-4 T and the dip angle is 30?
19. The graphs shown below depict the variation of current i m vs angular velocity for two different series LCR circuits. Observe the graph carefully; a. State the relation between the L and C values of the two circuits when the current in the two circuits is maximum. b. Indicate the circuit for which i. Power factor is higher ii. Quality factor (Q) is larger, Give reasons for each case. 20. A. Write the formula for the velocity of light in a material medium of relative permittivity Є r and relative magnetic permeability µ r. B. the following table gives the wavelength range of some constituents of electromagnetic spectrum. SL No Wavelength Range 1 1mm to 700nm 2 0.1m to 1mm 3 400nm to 1nm 4 <10-3 nm Select the wavelength range, and name the associated electromagnetic eaves that are used in; a. Radar systems of Aircraft navigation b. Earth satellites to observe growth of crops 21. A ray of light is incident on one face of a glass prism and emerges out from the other face. Trace the path of the ray and derive an expression for refractive index of the glass prism. 22. A convex lens of focal length 10cm is placed coaxially 5cm away from a concave lens of focal length 10cm. If an object is placed 30cm in front of the convex lens, find the position of the final image formed by the combined system.
IV. Value based question 1 X 4 = 4 Marks 23. Mr. Khanna a 65 year old person often complained of neck pain. One day his grandson Ayush, suggested that magnetic therapy is very effective in reducing such pains. He said that the permanent magnet/electromagnet, used in the device will help to produce Joule s heating effects in the blood stream, which helps the blood flow better. He immediately contacted his friend in Chennai, who was running Magnetic therapy Clinic. Mr. Khanna who felt better. a. What were the values exhibited by Mr. Ayush towards his grandfather? Mention any two. b. What is the SI unit of magnetic induction and define it? V. Long answer questions 3 X 5 = 15 Marks 24. A. Define electric flux and define its SI unit. B. Using Gauss s law, prove that the electric field at a point due to uniformly charged infinite plane sheet is independent of the distance from it. C. How is the field directed if the sheet is: - (i) Positively charged (ii) Negatively charged A. Define electric dipole moment. Is it a scalar or a vector? Derive the expression for electric field of a dipole at a point on the equatorial plane of the dipole. B. Draw the equipotential surfaces due to an electric dipole. Locate the points where the potential due to the dipole is zero. 25. A. Draw a schematic sketch of a cyclotron. Explain the role of crossed electric and magnetic field in accelerating the charge. Hence derive the expression for the kinetic energy acquired by the particles. B. An α-particle and a proton are released from the center of a cyclotron and made to accelerate. (i) Can both be accelerated at the same cyclotron frequency? Give reason to justify your answer. (ii) When they are accelerated in turn, which of the two will have higher velocity at the exit slit of the Dees? A. Derive and expression for the magnetic field at a point on the axis of a current carrying circular loop.
B. Two coaxial circular loops L 1 and L 2 of radii 3cm and 4cm are placed as shown in the figure. What should be the magnitude and direction of the current in the loop L 2 so that the net magnetic field at the point O is zero? 26. Derive the mirror formula which gives the relation between f, v and u. What is the corresponding formula for a thin lens? Trace the rays of light showing the formation of an image due to a point object placed on the axis of a spherical surface separating the two media of refractive indices n 1 and n. Establish the relation between the distance of the object, the image and the radius of curvature from the central point of the spherical surface. Hence derive the expression for the lens maker s formula. -----------********----------