12.Combine Test-2 (Paper-1)

COMBINED TEST - 2 (CT-2) PAPER-1 Duration : 3 Hours Max. Marks : 180 GENERAL INSTRUCTIONS 1. The question paper consists of three parts (Physics, Chemistry and Mathematics). Each part consists of three sections and total number of questions are 60. Marking Scheme 2. In Section 1 (Total Marks: 20), for each question you will be awarded 2 marks if you give the correct answer and zero mark otherwise. There are no negative marks in this section. 3. In Section 2 (Total Marks: 20), for each question you will be awarded 4 marks if you give the correct answer and zero mark if no answer is given. In all other cases, minus one (–1) Mark will be awarded. 4. In Section 3 (Total Marks: 20), for each question you will be awarded 4 marks if you give the correct answer and zero mark if no answer is given. In all other cases, minus one (–1) Mark will be awarded. SECTION - I (Single Correct Answer Type) This section contains 10 multiple choice questions, Each question has four choices, (A), (B), (C) and (D) out of which ONLY ONE is correct. 1. Consider the shown circuit. The capacitor is uncharged when the switch is closed at time t = 0. Which of the circuit given in options is equivalent to the shown circuit as t approaches infinity ? (A) (B) (C) (D) 2. In the capacitor discharge formula q = q0 e–t/ the symbol  represents : (A) the time it takes for C to loose q0/e charge. (B) the time it takes for C to loose charge q 1 1  0    e  (C) the time it takes for C to loose essentially all of its initial charge. (D) none of the above. 3. The resultant electric field at centre of a ring due to ring is zero. Which of the following is incorrect : (A) The total charge of the ring may be zero, although every part of the ring has charge. (B) The charge on the ring must be uniformly distributed. (C) The charge on the ring may be distributed nonuniformly. (D) Total charge on the ring may be positive. 4. In a series LR circuit, the voltage drop across inductor is 8 volt and across resistor is 6 volt. Then voltage applied and power factor of circuit respectively are: (A) 14 V, 0.8 (B) 10 V, 0.8 (C) 10 V, 0.6 (D) 14 V, 0.6 5. A conducting disc rotates about its axis (passing through centre and perpendicular to the plane of disc) in a uniform magnetic field B and magnetic field is perpendicular to plane of disc. There are certain points marked on a chord joining two points C and G on the periphery of the disc.Point E is the midpoint of the chord. Points D and F are the midpoints of segments CE and EG respectively. The emf induced is maximum between the points:(Do not consider the emf due to centrifugal forces) (A) C and D (B) C and E (C) C and G (D) D and F 6. Binding Energy per nucleon of a fixed nucleus XA is 6 MeV. It absorbs a neutron moving with KE = 2 MeV, and converts into Y, emitting a photon of energy 1 MeV. The Binding Energy per nucleon of Y (in MeV) is (A) (6A  1) (A  1) (B) (6A  1) (A  1) 7 (C) 7 (D) 6 7. In a series R  L  C circuit, the frequency of the source is half of the resonance frequency. The nature of the circuit will be: (A) capacitive (B) inductive (C) purely resistive (D) selective 8. If the readings of v1 and v3 are 100 volt each then reading of v2 is : (A) 0 volt (B) 100 volt (C) 200 volt (D) cannot be determined by given information. 9. In the ideal oscillating circuit, the capacitance of the capacitor is 25 F and has initial charge of 30 C. The inductance of coil is 0.04 H. The maximum magnitude of current in the circuit, after closing the switch K is (A) 10 mA (B) 30 mA (C) 60 mA (D) 3 mA 10. A thin uniform wire AB of length 1 m, an unknown resistance X and a resistance of 12  are connected by thick conducting strips, as shown in the figure. A battery and a galvanometer (with a sliding jockey connected to it) are also available. To obtain the value of X appropriate connections are made. Which one represents the correct combination if no deflection takes place in galvanometer. (A) (B) (C) (D) SECTION – 2 : (Paragraph Type) This section contains 4 paragraphs each describing theory, experiment, data etc. Eight questions relate to four paragraphs with two questions on each paragraph. Each question of a paragraph has only one correct answer among the four choices (A), (B), (C) and (D). 11. X-ray from a tube with a target A of atomic number Z shows strong K lines for target A and two weak K lines for impurities. The wavelength of K lines is 0 for target A and 1 and 2 for two impurities respectively. 0 0 1 = 4 and 2 = 1 . The screening constant of K lines is unity. Select the correct alternative(s) : 4  (A) The atomic number of first impurity is 2Z – 1 (B) The atomic number of first impurity is 2Z + 1 (C) The atomic number of second impurity is Z  1 2 (D) The atomic number of second impurity is Z + 1 2 12. White light travelling in air is refracted by water (A) It is possible that dispersion does not take place. (B) Dispersion necessarily takes place. (C) Red colour has highest speed in water. (D) If light is dispersed than violet colour undergoes maximum deviation. 13. A uniformly charged nonconducting disc having positive charge Q, is rotating about its axis with uniform angular velocity  as shown in figure. The magnetic field at the center of the disc is. (A) directed outward (perpendicular to plane of disc) 0Q (B) having magnitude 4 R (C) directed inwards (perpendicular to plane of disc) 0Q (D) having magnitude 2 R 14. A parallel plate capacitor of capacitance 'C' has charges on its plates initially as shown in the figure. Now at t = 0, the switch 'S' is closed. Select the correct alternative(s) for this circuit diagram. (A) In steady state the charges on the outer surfaces of plates 'A' and 'B' will be same in magnitude and sign. (B) In steady state the charges on the outer surfaces of plates 'A' and 'B' will be same in magnitude and opposite in sign. (C) In steady state the charges on the inner surfaces of the plates 'A' and 'B' will be same in magnitude and opposite in sign. (D) The work done by the cell by the time steady state is reached is 5 2C . 2 15. A battery of emf E and internal resistance r is connected across a resistance R. Resistance R can be adjusted to any value greater than or equal to zero. A graph is plotted between the current (i) passing through the resistance and potential difference (V) across it. Select the correct alternative (s) (A) internal resistance of the battery is 5 (B) emf of the battery is 10 V (C) maximum current which can be taken from the battery is 2 A (D) V-i graph can never be a straight line as shown in figure. SECTION – 3 : (Matching List Type) This section contains 4 multiple choice questions. Each questions has matching lists. The codes for the lists have choices (A), (B), (C) and (D) out of which ONLY ONE is correct. 16. Photons having energy equivalent to  line of lyman series can eject electrons from a metal. These electrons can excite H atoms upto n=2 level .If the maximum work function of the metal in eV , is , find the integer next to  17. An uncharged conducting sphere has a cavity inside it. a point charge 1 C is placed inside the cavity at the point A, shown in the figure.The dis- tance AB is 1 m. Consider the value of the dq r 2 where dq is a small charge element induced on the surface of the cavity and r is the distance from the element to the point B.The integration is to be done for all the charges induced on the inner surface of the conductor.If the value of the integral is p × 10-6 (in volt/m), find the value of p. 18. Two parallel infinitely long wires carrying currents in opposite directions so that repulsive force per unit length on wires is 0.1 N. The separation between the wires is 2m. If the mimimum magnetic field is k × 10–4 T exactly midway between the wires and in the plane of the wires. Then the value of k is : 19. A concave mirror of radius of curvature 10 cm is filled with water upto a very 4 small thickness ( = 3 ). Paraxial converging rays are incident of the system, whose intersection is 15 cm behind the mirror. At how much dis tance from the mirror, final image will be formed. Write the answer in cm 20. In the L–C circuit, the capacitor C1 is charged to a potential of 1 volt, and the capacitor C2 and the inductor were initially uncharged. 1.5  Now switch S1 is closed at t = 0, and at t = 100 sec. switch S2 0.5  is closed and S1 is opened. After 100 sec. , S2 is also opened. Find final potential difference across the capacitor C2 in volt. A nswers 1. (B) 2. (B) 3. (B) 4. (C) 5. (B) 6. (B) 7. (A) 8. (C) 9. (B) 10 (D) 11. (C, A,C) 12. (A,C, D) 13. (A,D) 14. (A,C,D) 15. (A,B,C) 16. 3 17. 1 18. 4 19. 3 20. 3