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(This question paper contains three printed pages) REHEARSAL TEST (2016-2017) SUBJECT:-- Physics. CLASS:--X. FULL MARKS:- 80. TIME:-- 2 hrs (Two Hours) Answer to this Paper must be written on the paper provided separately. You will not be allowed to write during the first 15 minutes. This time id to be spent in reading the Question Paper. The time given at the head of this Paper is the time allowed for writing the answers. Section 'is compulsory. Attempt any four questions from Section II. The intended marks for the questions or parts of the questions are given in brackets [J. Section - I (Compulsory) ~tate one factor on which the magnitude of a non-contact force depends. How does it depend on the factor stated by you? [2] ~ame ~n and define the S.I. and C.G.S. units of force. How are they related? [2] a see-saw, two children of masses 30 Kg and SOKg are sitting on one side of it at distances 2 m and 2.5 m respectively from its middle. Where should a man of 74 Kg sit to balance it? (2] . J9)'1 What is the position of centre of gravity of a: (i) Rectangular lamina (ii) Cylinder? (2] (~it possible to have an accelerated motion with a constant speed? Name such type of motion. [2] work done by a fielder when he takes a catch in a cricket match is negative. Explain. [2] ~he ~ boy of mass 40 Kg runs up a flight of 15 steps, each 15 cm high in 10 seconds. Find: [2] (if the work done and (if( the power developed by him. (c) A'A what way does the temperature of water at the bottom of a water fall differ from the temperature at U the top? Explain the reason. (Q)/J( cannon ball of mass 500 gm is fired with a speed of 15 m/sec. momentum. ~' [2] Find: (i) its kinetic energy and (ii) its [2] State two limitations of using wind energy for generating electricity. ~aYCompare ~hy (i) the ionizing power (ii) the penetrating power of a, ~ and" radiations. are the alpha particles not used in radio therapy? .(.c(How can the rate of emission of electrons in a cathode ray tube be increased? ~State two properties which a substance used as a thermionic emitter should possess. [2] (2] [2] [2] [2] ~ What is a carbon tax? Who shall pay this tax? [2] ~~tate the law of conservation of energy. [2] Page -1 of 3. (bYA ball of mass 0.20 Kg is thrown vertically upwards with an initial velocity of 20 m/sec. .(' Calculate the ~aximum potential energy it gains as it goes up. ~raw [2] a simple diagram to illustrate the action of the bicep muscle as a lever. Name the class of ~~ ~xPlain (~ve ~ how a gear system can be used to obtain gain in speed. [2] two reasons why the efficiency of a Single movable puHeysystem is not 100%? [2] Section - II (Any four) ~ (a)I'The refractive index of water is 4/3. Calculate the critical angle for water-air interface. J (Sin 49 = 3/4) [3] (~ A postage stamp kept below a rectangular glass block of refractive index 1.5 when viewed from vertically above it, appears to be raised by 7 mm. Calculate the thickness of the glass block. [3] j7) [4] v' State the conditions for each of the following: %:a lens has both its focal length equal. a ray passes undeviated through the lens. iVf 6. (a) Calculate the frequency of yellow light of wavelength 550 nrn. The speed of light is 3 X 10Bm/sec. [3] (b) Give one use each of (i) microwave (ii) ultraviolet (iii) infrared radiations. [3] (c) Name the rays or waves: (i) of highest frequency. (ii) used for taking photographs in dark. (iii) produced by the changes in the nucleus of an atom. (iv) of wavelength nearly 0.1 nm. ~at [4] is Sonar?Slatethe principleon whichit is based. ~ f [3] How do you tune your radio set to a particular radio station? Name the phenomenon involved in doing so and define it. [3] Jsi A man stands at a distance of 85 m from a cliff and fires a gun. After what time interval will he hear the echo, if the speed of sound in air is 340 m/sec. [4J 8. (a) A cell supplies a current of 2 A when it is connected to a 5 0 resistance and supplies a current of -1.2 A, if it is connected to a resistance of 9 O. Find the e.m.f. and internal resistance of the cell. ~ ~ ~w a labeled diagram of a three-pin socket. State the polarity of the solenoid shown below. State any two ways of changing it. [3J [3] [4] Page-20f3. 9. {a}/State V how the melting point of ice depends upon pressure. Explain why pressure cooker is used for (3] cooking food faster. u An equal quantity of heat is supplied to two substances A and B of same mass. The substances A shows a greater rise in temperature than B. What can you say about the specific heat capacity of A as compare to that of B. [3] (c)~ater at 15 C is falling from a height of 15 m from a water fall. If all the energy of falling water is ./ absorbed by it on striking the base of water fall, calculate the change in temperature of wa~er. [Take g 1p.('~ ../ [4] = 10 m/sec2] 25 Wand a 100 W bulb are joined in series and connected to the a.c. mains. Which bulb will glow brighter?E'KflcUV\. (3] ,~ame three factors on which the magnitude of force on a current carrying conductor placed in a magnetic field depends and state how does the force depend on the factors stated by you? yz{ Draw a labeled [4] diagram of a d.c. motor. --------- [3] END ------ Page-3 of 3.
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