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GAET VASANT VIHAR HIGH SCHOOL AND JUNIORCOLLEGE GRADE:10 DATE: 15-01-25 PRE BOARD EXAMINATION 2024-25 MARKS: 80 TIME: 2 HOURS SUB: SCIENCE PAPER I- PHYSICS NAME: ROLL NO: DIVISION NO. OF PAGES: 10 Answers to this paper must be written on the paper provided separately. You willnot be allowed to write during first 15 minutes. Thistime is to be spent in reading the question paper. The time given at the head of this paper isthe time allowed for writing the ans wer. Section Aiscompulsory. Attempt any four questions from Section B. The intended marks for questions or parts of questions are given in brackets I ) Question 1 [15] Choose the correct answers to the questions from the given options. (Do not copy the question, write the correct answers only.) 1 Adoor lock is opened by turning the lever (handle) of length 0.2 m. If the moment of force produced is 1 Nm, then the minimum force required is 2. (d) 0.2 N (b) 10 N (c) 20 N (a) 5 N The diagram below shows the balanced position of a meter scale. 0 10 20 A 50 60 70 80 90 100 Fukrua Which one of the following diagrams shows the correct position of the scale, when it is supported at the centre? a. ) 0SA 60 :30 Fulcrunn |0 20 0 70 S0 00 b. lu 0 ) 0 30d Fuereta 0 SO 90 0) d. C. 0 10 20 30 40 50 60 70 80 90 100 Fulcun 3 The kinetic energy of a given body depends on the: (a) position (c) momentum T 23 512 PAGE 1 (b) centre of gravity of the body (d) displacement TURN OVER v VVHS&JC/GRADE 10 4, SUB: SCIENCE PAPER |- PHYSICS 15.01.2025 Assertion : When the furce retards the motion ofa body, the work done is zero. Reason: Work done depends on angle betweenforce and displacement. (a)Both assertion and reason are true and reason is the correct explanation of assertion. (b)Both assertion and reason are true but reasonis not the correct explanation of assertion. (c)Assertion is true but reason is false. (d)Assertion is false but reason is true. Assertion (A): In a second-class Iever, the load is located between the fulcrum 5. and the effort. Reason (R): Second-class levers always provide a mechanical advantage greater than 1. - (a)Both assertion and reason are true and reason is the correct explanation of assertion. (b)Both assertion and reason are true but reason is not the correct explanation of assertion. (c)Assertion is true but reason is false. (d)Assertion is false but reason 6. conductor ABis kept along North-South direction of the earth above a magnetic A needle as shown below. When the key Kis closed, then B A W Magnetic ncedle K, (a) the needle will not show any deflection. (b) the needle willdeflect towards East. 7. i.e. towards South. (c) the needle will turn in the opposite direction (d) the needle willdeflect towards West. to from an optical medium of refractive index 1.33 ray of light passes obliquely A from the first medium to the another medium of refractive index 1.5. While passing second, the light ray will: (b)bend away from the normal. (a)bend towards the normal. (d)suffer totalinternal reflection. (c)move along the normal. T23 512 PAGE 2 TURN OVER V H & VVHS & JC/GRADE 10 15.01.2025 SUB: SCIENCE PAPER I PHYSICS Violet, gseen, red and yellow are the four colours formed on awhite screen when a 8. polychromatic light is dispersed. The arrangement of colours in the decreasing order of wave lengths is : (b)violet, green, yellow and red (d)violet, green, red and yellow (a) red, yellow, green and violet (c)green, red, yellow and violet When a cell is in use 9 (a) its terminal voltage is equal to the electromotive force. (b) its terminal voltage is greater than the electromotive force. (c) its terminal voltage is less than the electromotive force. (d) the relation between its terminalvoltage and electromotive force depends on its internal resistance. 10. The symbols for 5 different nuclides are given below: X Nuclide 1 Nuclide 2 38Y X 184 Nuclide 3 Nuclide 4 X Nuclide5 Which two nuclides are isotopes of the same element? a) Nuclide 1 and Nuclide 2 b) Nuclide 4 and Nuclide 5 c) Nuclide 2 and Nuclide 3 d) Nuclide 2 and Nuclide 5 11. During melting of ice at 0 C the (a)energy is released and temperature remains constant. (b)energy is absorbed and temperature remains constant. 12. (c)energy is released and temperature decreases. (d)energy is absorbed and temperature increases The adjacent figure shows the connecting points of a socket outlet. Which of the following gives the correct order of the connections which are made to the pins marked 1, 2&3 respectively. (a)Live, Neutral, Earth (c) Earth, Neutral, Live 13. (b) Live,Earth, Neutral (d) Earth, Live, Neutral By reversing the direction of current in an electromagnet, the magnetic field produced by it (a) remains unchanged in strength and direction. . (b) gets reversed in direction. (c) increases in strength. (d) decreases in strength. 14. The ratio of velocities of light of wavelength 400 nm and 800 nm in vacuum is (b) 1:2 (d) 1:3 (a) 1:1 (c) 2:1 15. A converging lens has a focal length 40 cm. The power of this lens is. (d) + 1.5D (b) +2.5D (c)-1.5 D (a) - 2.5 D T 23 512 PAGE 3 2/S TURN OVER VVH vVHS &JC/GRADE 10 SUB: SCIENCE PAPERI- PHYSICS 15.01.2025 QUESTION 2: Complete the following by choosing the correct answer from the bracket a. A geyser/battery/thermocouple) converts heat energy to electrical energy. b. Raising body weight on toes is an example of_ lever. C. If a lens is placed in water instead of air its focal length (class /classll/ classill) remains same) d. The temperature versus time graph for three substances A,B,C ii. (6] (increases/decreases/ is shown below. If heat supplied to all of them is at equal rates then the substance with lowest heat capacity is (A/B/C) femp e. 1g of water at 0 C contains (less /more/equal) heat than 1g of ice at 0 C f. The lens used in correcting Time (t) hypermetropia produces (realand erect/ virtual and erect/ real and inverted) image on the retina. The diagram below shows a bultb connected by dual control switches. Observe the diagram and answer the questions: A [2] B a. Which of the above circuits willbe able to switch ON or Switch OFF the bulb using both the switches? b.At present in which circuit is the bulb glowing? Atransformer is used to change a high alternating e.m.f to a low alternating e.m.f of [2] Question 3 1. Two forces F1 = F2 are applied ona wheel of 1.5 m radius, such that moment of couple is 30Nm. Calculate the magnitude of each of the force. (-S (21 same frequency. a. ldentify the type of transformer used for the above purpose. b. State whether the turns ratio for the above transformer will be =1,>1 or<1 T 23 512 PAGE 4 TURN OVER 15.01.2025 SUB: SCIENCE PAPER I- PHYSICS VWHS &JC/GRADE 10 a nut Awalnut can be broken by applying a direct force of 54 kgf. If the walnut is placed in 2. cracker, the length of whose handle is 18 cm andnut is placed 2 cm from the pivot, calculate the minimum force required to crack the nut. and other 3. a. Name the technique used to estimate the age of very old trees, plants, wood (2] (2] such specimens. b. Name the isotope that forms the basis of this technique. Two wires A and Bof copper are of the same length having radii r1 and r2 respectively and 4. (2] if i< 2 then state true or false for each of the two statements a. resistance of A<resistance of B. b.resistivity of Aand Bis the same. ditesng The diagram below represents the image formed by a canverging lens 5. (2] object O principal P axis R image 6. a. Which distance represents the focal length of the lens? b. Give one application of the above type of image formation as shown in the diagram. State the function of split rings in a d.c. motor. 7. A vibrating tuning fork is placed over the mouth of a burette filled with water. The tap of (2] [3] the burette is opened and the water level gradually starts falling. It is found that the sound from the tuning fork becomes very loud for a particular length of water column. Tuning Fork (a) Name the phenomenon taking place when this happens. (b) Why does the sound become very loud for this length of water column? T 23 512 Air coBumn Burette PAGE 5 TURN OVER VVHS &JC/GRADE 10 SUB:SCIENCE PAPERI- PHYSICS 15.01.2025 SECTION-B (Attempt any four questions from this Section) QUESTION 4 1. Aball of mass m is dropped freelyfrom point A. It is given that AB = BC = CD=h. If the [3 acceleration due to gravity at the given place isg, then what will be its (a) potentialenergy at point A? (b) kineticenergy at point C? h +B h h 2. Observe the figure shown below and answer the questions: [3] a. ldentify the device. b. State the frequency range of the waves used in the above device c. Give one property which makes it suitable for its use in the device stated by you in(a) 3. A person standing between twO vertical cliffs and 640 m away from the cliff, produces sound. He hears the first echo after 4 seconds and the second nearest echo 3 seconds [4] later. Calculate a. the speed of sound in air b. the distance between the cliffs T 23 512 PAGE 6 TURN OVER JC/GRADE10 yHS& 15.01.2025 SUB: SCIENCE PAPERI- PHYSICS QUESTION5 3] coin kept in a beaker is not visible when seen from 1 A point P on one side. But, when water is poured in the beaker,the coin becomes visible from point P. a. Which is the physical quantity represented by ratio AC: AB? b.What difference willyou observe in height AB if water is replaced by glycerine? c. Write your observation when the coin A B is viewed from point Q. C system Draw a labelled diagram of the 3. ratio velocity has system 2.. a. A block and tackle effort E. and the direction of load Land indicating the points of application distance of b. If the effort end moves a 60 cm, what distance does the shows the path of light 3 a. The diagram below angled prism of passing through a right tillthe the diagram critical angle 429. Complete ray A emerges out b. Name the face of [3] load move? [4] 30 of the prism. the prism that behaves as a reflecting surface (V) D1fference Potential QUESTION 6 1 [3] different vs current for four The graph of voltage materials is shown below. would have more a.Which of these four materials conductance? -G PAGE 7 T23 512 Electric current () TURN OVER vVHS &JC/GRADE 10 15.01.2025 SUB: SCIENCE PAPER |- PHYSICS b. Roan connected a circuit as shown in the figure. He wantcd to findcurrent and potential difference when the resistors are connected in parallel. ldentify the fault in the connections made by Roan and rectify it by redrawing the figure 2. The hammer throw is an athletic event. The athlete throws a heavy metal ball attached by [3] awire to a handle. Anticlockuiw: Fig 1 Fig 2 The hammer thrower swings the hammer round in a circle before letting go. He swings the hammer slowly at first and then faster. The Figure 2 shows an overhead view of ahammer thrower swinging the hammer anticlockwise in a circle. (0) In which direction, A, B,Cor Ddoes the centripetal force act on the hammer? (ii)Complete the following sentence by correct word The centripetal force is provided by the.. (Tension in the wire/stress in the wire) (ii) At the instant shown inthe diagram above, the athlete lets go off the handle. Inwhich direction, A, B, Cor D, does the hammer move? Acar of mas 120 kg is moving at a speed of 18km/h and it accelerates to attain a speed of (4] 54 km/h in 5 seconds. Calculate : a. the workdone by the engine b. the power of the engine 36 T 23 512 PAGE 8 TURN OVER VHS &JC/GRADE 10 SUB:SCIENCE PAPERI PHYSICS 15.01.2025 QUESTION7 1. AB is anobject and PQ is its real, inverted image.The lengths of AB and PQ are equal. This is possible when a lens is present between the object and its image. Complete the ray diagram using suitable lens. arrow shows the motion of the bar magnet 2. In the given diagram alongside an SOLENoD solenoid. towards the 3] [3] MAGNET 3 formed at the end A left? (a) State the pole galvanometer(G) deflects, left to right or right to the direction which in (b) State conclusion. to come to the (c) Name the law used at a distance 60 cm from the 20cm forms an inverted image length focal of lens convex A [4) lens. front the object? i. How far is the lens kept in the image. . Calculate the magnification of QUESTION & 1. curve for a The diagram below shows a cooling substance: (a) State the (3] |tcmperature C temperatures at which the substance condenses. which the substance is (b) The temperature range in in liquid state. ice-cold water for (c) Why do we prefer ice to cooling a drink? 150 60 10 (0.0) PAGE 9 T 23 512 TURN OVER VVHS &JC/GRADE 10 2 15.01.2025 SUB: SCIENCE PAPERI- PHYSICS a. Why does the sun appear reuat surise and sunset? [3] b. What characteristic property of light is responsible for the blue colour of the sky? 3. Calculate the mass of ice needed to cool 150 g of water contained in a calorimeter of mass (4] 50 g at 32 C such that the final temperaure is 5 C. Specific heat capacity of calorimeter =0.4 J/g C Specific heat capaity of water = 4.2 J/g C Latent heat capacity of ice=330 J/g QUESTION 9 1. Aradioactive nucleus undergoes a series X X1 of decays according to the sequence : (3] X3 If the mass number and atomic number of X3 are 172 and 69 mass number and atomic number of X? respectively, what is the 2. A mixture of radioactive substances gives off three types of radiations. (i) Name the radiation which travels with speed of light. [3] (i ) Name the radiation which has the highest ionising power. (i ) Name the radiation that is attracted towards the positive plate when subjected to an electric field? 3. Three resistors 82, 122 and 62 are below. Find: connected to a 12 V battery as shown in the figure 12V 12S2 8S2 62 (i) the current through 8 N resistor. (i ) the potential difference across the parallel combination of 6 2 and 12 Q resistors. (iii) the current through the 6 2 resistor. T 23 512 PAGE 10 [4]
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