Section-1 Physics 1. If 3.8 × 10-6 is added to 4.2 × 10-5 giving due regard to significant figures, then the result will be : 1) 4.58 × 10-5 2) 4.6 × 10-5 3) 4.5 × 10-5 4) None of these 2. A ball is dropped from a bridge at a height of 176.4 m over a river. After 2 s, a second ball is thrown straight downwards. What should be the initial velocity of the second ball so that both hit the water simultaneously ? 1) 2.45 ms-1 2) 49 ms-1 3) 14.5 ms-1 4) 24.5 ms-1 3. Which of the following are true ? 1. A body having constant speed can have varying velocity. 2. Position time graphs for two objects with zero relative velocity are parallel. 3. The numerical ratio of velocity to speed of an object can never be more than one. 1) 1 only 2) 2 and 3 3) All 4) None of these 4. The centripetal acceleration of a body moving in a circle of radius 100 m with a time period of 2 s will be 1) 98.5 ms-2 2) 198.5 ms-2 3) 49.29 ms-2 4) 985.9 ms-2 5. How many NAND gates are used in an OR gate? 1) Four 2) Two 3) Three 4) Five

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6. A 5000 kg rocket is set for vertical firing. The exhaust speed is 800 ms-1. To give an initial upward acceleration of 20 ms-2, the amount of gas ejected per second to supply the needed thrust will be (g = 10 ms-2) 1) 127.5 kg s-1 2) 187.5 kg s-1 3) 185.5 kg s-1 4) 137.5 kg s-1 7. Induction furnace is based on the heating effect of 1) electric field 2) eddy current 3) magnetic field 4) gravitational field 8. A 5.0 μF capacitor is charged to a potential difference of 800 V and discharged through a conductor. The energy given to the conductor during the discharge is 1) 1.6 × 10-2 J 2) 3.2 J 3) 1.6 J 4) 4.2 J 9. If the electric field is given by (5i + 4j + 9 ), the electric flux through a surface of area 20 unit lying in the Y-Z plane will be 1) 100 unit 2) 80 unit 3) 180 unit 4) 20 unit 10. An aluminium (Al) rod with area of cross-section 4 × 10-6 m 2 has a current of 5 A flowing through it. Find the drift velocity of electron in the rod. Density of Al = 2.7 × 103 kgm -3 and atomic wt. = 27 u. Assume that each Al atom provides one electron. 1) 8.6 × 10-4 ms-1 2) 1.3 × 10-4 ms-1 3) 2.8 × 10-2 ms-1 4) 3.8 × 10-3 ms-1 11. Taking the internal resistance of the battery as negligible, the steady state current in the 2Ω resistor shown in the figure will be

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1) 1.8 A 2) 2.9 A 3) 0.9 A 4) 2.8 A 12. Which statement is true ? 1. Kirchhoff's law is equally applicable to both AC and DC. 2. Semiconductors have a positive temperature coefficient of resistance. 3. Meter bridge is greater sensitive when the resistance of all the four arms of the bridge are of the same order. 4. The emf of a cell depends upon the size and area of electordes. 1) 1 and 4 2) 2 and 4 3) 3 and 4 4) None of these 13. Six resistors, each of value 3 are connected as shown in the figure. A cell of emf 3 V is Ω connected across AB. The effective resistance across AB and the current through the arm AB will be

1) 0.6 Ω, 1 A 2) 1.5 Ω, 2 A 3) 0.6 Ω, 2 A 4) 1.5 Ω, 1 A

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14. If t1 and t2 are the times taken by two different coils for producing same heat with same supply, then the time taken by them to produce the same heat when connected in parallel will be 1) t1t2/(t1 + t2) 2) t1 + t2 3) t1t2 4) (t1 + t2)/t1t2 15. In a p-n junction diode, a square input signal of 10 V is applied as shown in figure. The output signal across RL will be

1)

2) 3) 4)

16. Neutrino emission in β-decay was predicted theoretically by 1) Planck 2) Heisenberg 3) Laue 4) Pauli 17. A telescope consists of two thin lenses of focal lengths 0.3 m and 3 cm respectively. It is focused on moon which subtends on angle of 0.5° at the objective. Then, the angle subtended at the eye by the final image will be 1) 5° 2) 0.25° 3) 0.5° 4) 0.35° 18. A ray of light passes through an equilateral prism such that the angle of incidence is equal to the angle of emergence and the latter is equal to (3/4)...