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RBK RBK School SCHOOL MXACH EYOND (Managed by Babubha Kanakia Foundation) School Code: MA069 SECOND PRELIM EXAM 2024-25 Grade: 10 Subject: PHYSICS Max. Marks:80 Date: 06/01/25 Dur. :2 Hrs Number of printed pages : 8 SECTION A (Answer all questions in this section) QUESTION 1 15 (0) Which has greater resistance, the flament of a 60W bulb or a 40W bulb? (a) 60W (b) 40W (c) both have the same (d) cannot be determined (0) The potentialenergy of a person is minimum when, (a) person is standing (b) person is sitting on a chair (c) person is sitting on the ground (d) person is lying on the ground (n) Aray of light enters from medium Binto medium Aas shown. The refractive index of medium B relative to A will be (a) greater than unity Medium A (b) less than unity (c) equal to unity Medium B (d) zero (v) The material of the core of a strong electromagnet is, (a) steel (b) soft iron (c) wrought iron (d) brass 1 11-12 RBK School CSE-Grade 1-10 &ISC - Grade wa tkhool og norbschool org functions (V) Atransformer when connected to, (a) dcsource (b) a c sOurce (c) either (a) or (b)can be connected (d) none of them () f the by one, then the position of a daughter nucleus shifts radiation emitted by'the radioactive nucleus is, (b) B (a) a (c) a and then y (c) y (vii) Afuse works on, (a) the magnetic effect of electric current (b) the chemical effect of electric current (c) the heating effect of electric Current (d) none of the above (vii) Assertion: The neutral wire and the earth wires are connected to same potential. Reason: The live wire carries current back to the source. (a) Assertion is true, Reason is false. (b) Assertion is false, Reason is true. (c) Both Assertion and Reason are false. (d) Both Assertion and Reason are true. (ix) The sound level in decibel, which has a soothing effect, is, (a) 90 - 120 dB (b) 0 - 10 dB (c) 20 - 20k dB (d) 10 -30 dB (x) Aray of light of a given angle of incidence lalls on the surfaces given below, in which surface will the angle of refraction be the least, (a) water (b) diamond (cSint glass (d) crown glass 2 RBK Schorl Grade 1-10 & 1SC - Grade 11-12 kechool.org (Xi) An iron sphere of mass 30kg has the same diameter as an aluminium sphere of mass 10.5kg.The spheres are dropped simultaneously fromacliff. When they are 10m trom the ground they have the same, (a) acceleration (b) potential energy (c) kinetic energy (d) momentum (xi) Aglass tumbler rest on a table. When slightly tited, its CG will, (a) remain unchanged (b) rise (c) displaced horizontally (d) fall (xii) If a block and tackle system with a convenient direction has 3 movable pulleys, then its VR will be, (a) 8 (b) 7 (c) 5 (d) 4 (xiv) Light rays are not used in, (a) CAT scan (b) spectrometer (c) crystal oscillators (d) to take the image of the human heart. (xv) Aconvex lens forms a virtual and erect image if the object is placed, (a) at infinity (b) between F and 2F (c) between optical centre and focus (d) at focus &ISC - Grade 11-12 pEK School CSE -Grade 1-10 teelerg info@rbkschool.org ( ) 6 QUESTION 2 (refraction, reflection, total internal reflection) of light. ) a. Stars twinkle due to, b. Heat supplied to a substance, causes no change in the temperature of the substance, (KE, PE, both KE and PE) then the substance shows an increase in C. A freely suspended pendulum in air is disturbed once and left to oscillate on its own, (damped, forced, natural). the type of vibrations exhibited by the pendulum is, d. Astone of mass m',is rotated in a circular path by holding a strong string atached toit. with your hand, then stone moves with (uniform, variable) acceleration, and the force acting on the hand is the (centripetal, centrifugal, gravitational). (conduction, e. The wOoden lid in a calorimeter prevents heat loss by, convection,radiation) (i) Asingle fixedpulley is used to raise a load of 27N from the ground to the first floor of a building. if the efficiency of the systen is 90%, find the frictional force experienced on applying an the effort. 2 2 (ii) Define 1kWh. Express in the Sl unit. QUESTION 3 (i) a) What does the gradient of an |-V graph help determine? b)Obtain the resistance of the conductor from the graph given. 15 10 5 3 6 12 4 RBK School" iCSE- Grade 1-10& ISC -Grade 11-12 wwwrbl schccl or] info@rbkschool.org V 3 ( ) While conducting an experiment, Sam needs to deviate arayoflightby 90 . llustrate how it would be possible with the usefield of a pris. (ii) State 2 ways by which the magnetic of a solenoid can be made stronger. (iv) List two characteristics of a fuse (V)Aray of light is incident on diagram. wire. 42 .Copy and complete a prism of critical angle 2 the 43 section are at 30 C. If length cross of area same the B, of (VI) TWo copper wires A and resistance? then, a) Which wire has greater B, of length the twice is of A resistivity? b) Which wire willhave greater the principal concave lens emerges parallel to a through refraction (vii) A ray of light, after ray. show the incident and emergent axis. Draw a ray diagram to 2 2 SECTIONB (Answer any FOUR questions in this section) Question 4 undergoes an a decay and changes to radium. 28Th isotope (i) A thorium produced? and mass number of the radium a. What is the atomic number disintegration and emits a Bparticle, represent this b If the radium undergoes a further equation. reaction in the form of an shows a solenoid AB. ( ) The diagram at end A? a. What is the polarity electromagnet two advantages of an 3 SOLENOID b. Give over a permanent magnet. 3 &ISC -Grade 11.12 School ICSE-Grade 1-10 PRK .wwtkshool org info@rbkschool.org (i) Three resistors are connected as shown in the diagram. Acurrent of 1ampere fowe through the 5 ohm resistor. 4 a. What is the current through the other two resistors? b.What is the total resistance of the given combination? 10 2 A S2 B C 1anp. QUESTION 5 () Abody of mass 10kg is kept at a height of 5m. It is allowed to to fall reach the ground. a. What is the total mechanical energy possessed by the body at the height 2m, assuming it is a frictionless medium? b. What is the kinetic energy possesed by the body at the same height of 2m. () Aboy tunes his radio channel to a popular musical radio station 98.4 MHz. a. Define the phenomenon involved in tuning the radio channel? b. What is the frequency of the channel in the Sl system? 2 (ii) Name the following: 5 a. The phenomenon of the occurance of a mirage. b. The principle of a transformer C. The effect by which on reflection, sound gets prolonged. d. The phenomenon by which diamonds sparkle. e. The correction lens for hypermetropia. 6 S-Grade 1-10 &ISC- Grade 11-12 -kschool org QUESTION 6 i "The power voltage rating of an electric bulb is 80W-200V. a. What is meant by the above statement? b. What will be the safe current that can pass through the bulb? c. What is the resistance of this bulb? (i) Drawa neat labelled diagram of a step - up transformer. Why is its core made of soft iron? 3 (i) When radiation Pfrom a device is focused on the bulb of athermometer, its mercury level showed a significant rise. 4 a. Name the radiation P. b. What is the wavelength range of radiation P. c. List 2properties by which radition P differs from all other radiations. QUESTION 7 (i) What is meant by nuclear waste. Suggest two effective ways for the safe disposal 3 of nuclear waste. (ii) a. Define,'internal resistace of a cel'. Mention a factor on which it depends. b. Give an expression to relate e.m.f. and internal resistance of a given cell. 3 (i) a. AConvex lens has a real focus. Justify 4 b. State two factors that affect the focal length of a lens. QUESTION 8 () the characteristics of a. Draw a neat labelled diagram of an electric socket, showing the terminals. b. The refractive index of glass is 1.5. Explain. areaction. In) The chemical olements Ar and X are used in a f y the shove cloments. b. How many protons and neutrons are in 3 3 Ar. (o) With reference to the diagram shown, answer the following. a. ldentify the above device. b What is the primary function of this device. c. Mention two ways by which the output efficiency of the device be increased. coil J1Dagnet nagret QUESTION 9 () a. Aburner raises the temperature of 360g of water from 40 C to 100 C in five minutes.Calculate the rate of heat supplied by the burner. 3 b. Relate the intensity of scattered light to its wavelength. ( ) a. An observer stands at a distance of 850m from a cliff and fires a qun. After what time interval will he hear an echo, if the speed of sound is 350m/s b. ldentify the energy transformation when a loud speaker is in use? 3 (ii) a. What is the effect of 1. temperature on the resistance of a semiconductor? 2. pressure on the boiling point of a liquid? b. Calculate the electrical energy consumed when a bulb of 40W is used for 12.5 hour every day for 30 days. 4 8 RBK School 1CSE- Grade 1-10 &ISC-Grade 11-12 www.rbkschool.org " info@rbkschool.org
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