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MIDTERM EXAMINATION [2023-24] Std : X Total MarkS : 80 PHYSICS (SCIENCE PAPER-1) Time allowed: Two hours Answers to this Paper must be written on the paper provided separately. You will not be allowed to write during first 15 minutes. This time is 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 A is compulsory. Attenmpt any four questions from Section B The intended marks for questions or parts of questions are given in brackets [J. SECTION A (Attempt all questions from this Section.) Question i Choose the correct answers to the questions from the given options: (i) For which object position the image formed by a convex lens is of equal size of the object? (a) At F1 (b) At 0 fo) At 2F1 (d) Between F1 and O (ii) Fuse wire is always fitted in a porcelain casing because porcelain is: (a) Insulator (b) Conductor (c) Flexible (d) Rigid (ii) Which of the following is a correct mathematica! relation? (a) power= force/ velocity (b) power = force x acceleration (c) power-force/acceleration (iv) (d) power-force x velocity Which of the following ray produces vitamin D in human body? (a) ultraviolet (b) infrared (e) visible light (d) all of these [15] (v) Assertion: centripctal force can be considered as the rcaction force of centrifugal forcc. (vi) Keason: centripctal force acts along the radius and away Iromthe ccntre of the circle. (a) both assertion and reason are true (b) assertion is false but reason is true. (c) both assertion and reason are false. (d) assertion is true reason is false. Unit of specific resistance is (a) Qm (b) S2m' (c) Q (d) Qm (vii) When the speedof a moving object is doubled, then its kinetic energy: (a) doubled (b) remains the same (c) decreases (vii) my? 2 (d) becomes four times When a current I flow through a wire of resistance R for timet then the electrical energy produced is given by: (a) TRt (b) IR?t (ix) (c) IR{? (d) IRt Choose the correct relation for e.m.f. ([) and terminal voltage V: (a) &=V [always] (b) e <V [always] (c) &>V[always] i) none of these (x) Small air bubbles rising up a fish tank appear silvery when viewed from some particular angle is due to the: (a) reflection (b) refraction (xi) (c total internal reflection (d) dispersion When the resistance of the combination to be decreascd, they are connected in (a) combination of series and parallel (b) series (c) parallel (d) in any of the way (xii) How much light energy (approx) isreflected back in total internal reflection? (a) zerO (b}100% (c) 75% (d) 90% (xii) Ablock and tackle pulley system has n pulleys. If the load moves up through a distance ofd, theeffort end moves up through a distance of: (a) d (b) d+nd (C} nd (d) d/n (xiv) t N n d d The graph plotted for potential difference (V) against current (1) for ohmic resistors is: (a) A curve passing through the origin. (b) A straight line not passing through origin. (c) A straight line passing through the origin. (xv) (d) A circle centered at the origin. An electric bulb is marked 60W-230V. What current does it take? (a) 0.235A (b) 0.465A ce) 0.260A (d) 0.561A Question 2 (i) (a) A satellite revolves around a planet in acircular orbit. What is thework done by the satellite at any instant? (b) What are super conductors? (c) State the condition for the validity of ohm's law. (ii) Write two advantages of connecting the appliances in parallel? (a)State and define the S.I. unit of power. (ii) (iv) (b) How is the unit horse power related to the S.1. unit of power? How does the thickness and length of a fuse wire depend on its [3] [21 (2] [2] current rating? (v) It is dangerous toconnect switch in the neutralwire. Explain your answer. [2] (vi) The following diagram shows a 60 , 30 , 90 glass pris1m of [2] eritical angle 42 , Copy the diagram and complete the path of incident ray AB emerging out of the prism marking the angle of incidence on each surface. 60 B TT (vii) 30z A Observe the diagram which shows the path of an incident ray through an optical plane LL' of a lens. The focal length of the lens [2] is 20 cm. 2F 21 (a) Namne the sightedness that can be corrected using this lens. (b)Write the nature of the image formed when the object is placed at a distance of 30cm from the lens. Question 3 (i) State the condition for a body to be in () static (ii) (ii) equilibrium and (b) dynamic equilibrium. Why is the ratio of velocities of lights of wavelengths 4000 and 8000 invacuum 1:1? Which of the above wavelength has a [2] higher frequency? (a) Identify the class of the lever shown in the diagram below. (b)How is it possible to increase the M.A. of the given lever [2] without increasing its length? E [2] 2 (iv) There are four convex lenses A, B, C, D of focal length 10cm, 20cm,60cm and 100cm.Identify the lens with highest power. Justify your answer. There are m resistor each of resistance R. First, they all are are connected in series and equivalent resistance is X. Now they the connected in parallel and equivalent resistance is Y. What is [2] [2] ratio ofX and Y? SECTION B (Attempt any fourquestions,) Question 4 () travelling through an The diagram below shows the ray OP equilateral prismn of a certain material. angle of deviation is 43". (a) Calculate the value of iz, if the (3] (b) What is the ray OS called? (ii) (iii) force, where and in what Toopen aheavy gate using minimum direction should the force be applied? Why? and works on 250 V (a) An electric bulb draws a current of 0.8 A power consumed by the on theaverage 8 hours a day. Find the [3] [4] bulb. and 62 be (b) How can three resistors of resistances 2 2, 3 2 connected to give a total resistance of 4 Q? Question 5 i) The figure alongside shows a simple pendulum of mass 200 g. It is displaced from the mean position A to the extreme position B. The potential energy at the position A is zero. At the position B the pendulum bob is raised by 5 m. (given, g-10m/s) B 5 m .... [3] (a) What is the potentialenergy and kinctic energy of tlhe pendulum at the position B? (ii) (b) What is the total mechanical cnergy at point C? Ablock andtackle system of pulleys has velocity ratio 4. [3| (a) Draw a labelled diagram of thesystem indicating clcarly, the directions of load, cffort and tension. (b) What is the valuc of the mcchanical advantagc of the given pulley system if it is an idcal pulley system? (iii) Consider thedata in the table shown where current in three different electrical appliances exists if the appliances are connected 14] to240V supply. Basedon the data shown, answer the following questions. Appliance Current Kettle 8.5A Lamp 0.4A Toaster 4.8A (a) Which appliance has greatest electrical resistance? (b) What is the power rating of the toaster? P- Totala (c) A man takes the kettle abroad where the main supply is 120V. Calculate the current passing through the kettle when it is operated in 120V supply. Question 6 (i) A virtual, magnified image is formed when the object is kept in front of a lens. Draw a ray diagram to show the formation of image [3] with the above characteristics. (i) (iii) (a) State the lens formula. Howdoes f change when the object distance u from the lens changes? (b) Name the lens with negative power. (a) Define a kilowatt hour. (b) State and explain any three factors affecting the resistance of a [3] (4] conductor. Question 7 (i) (a) Is it possible that a glass slab disperses the light? Explain your answer. (b) Name the high energetic invisible electromagnetic wave which helps in the study of the structure of crystals. [3] (ii) Find the cquivalent resistance between points A and B. [31 A (iii) (a) Draw the diagram of a dual control switch when the appliance [4] is switched 'ON'. (b) Name the colour code of the wire which is connected to the metallic body of an appliance. (c) State the relation between critical angle and absolute refractive index of a medium. Question 8 (i) The diagram below shows a light source P embedded in a rectangular glass block ABCD of critical angle 42 . Complete the [3] path of the ray PQ till it emerges out of the block. [Writenecessary angles] F C 420 P D (ii) (ii) A uniform metre scale is supported at the 40cm mark. obtained when a 45g mass is suspended at the Balance is 10cm mark. Draw a diagram to show the application of forces and determine the weight the of the metre scale. (a) A force acts on a body and displaces it by a S in a direction at an angle with the direction of distance force. What should be the value of 0 to get the maximum positive work? (b) State the energy change in the following cases while in use: 1) An electric iron 2) A ceiling fan [3] [4] Question 9 () (a) Name the four colours of spectrum of white light which has wavelength longer than the blue light. Also name the light amongst the given, which shows maximum deviation. 3] (b) Write one consequence of scattering of white light. (ii) Aboy uses a single fixed pulley to lift a load of 50 kgf to some height. another boy uses a single movable pulley to lift the same load to the same height. Compare the effort applied by them.Give a reason to (iii) (a) Write the SI unit of linear magnification. (b) A metallic wire of resistance R is cut into ten parts of equal [3] support your answer. length. Twopieces each are joined in series and then five such combinations are joined in parallel. What will be the effective resistance of the combination? [4]
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