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RBK RBK School, Mira Road (Managed by Babubhai Kanakia Foundation) SDO, School Code: MA069 PRELIM 1 2020-21 Std: 10 Marks: 80 Date: 10/03/21 Subject: PHYSICS Dur.: 2 Hours SECTION 1 (ANSWER ALL QUESTIONS IN THIS SECTION) Q1.a. State the conditions under which work done b. For 2 single movable pulley, select the appropriate option, a i)MA i) 2 2, VR = 1, Speed multiplier. MA 2, VR 2, Force = multipiier. i) MA 1, VR = 1, convenient direction iv) = 2, Force = c. by a force is positive. MA 1, VR of effort. multiplie. Copy the geometrical lamina drawn below to obtain the position of its center of 2 gravity. Mark G in the diagram. d. Calculate the amount of heat energy gained when 0.6kg of water at 28 C is brought to its boiling point. eThe refractive index of diamond is 2.42. What is meant by this statement? Q2. a. Define Power. b. A nucleus Li, form a Express it in terms of two derived quantities. having atomic number 3 and nucleus Be. Write the mass no. 7, emits symbolic equation of the An object placed is at a distance X from 15cm from the lens. If the focal RBK School, Mira Road |ICSE Std 1 to 10 www.rbkschool.org info@rbkschool.org a convex 2 2 a beta particle to process and what is the general name of the product nucleus formed with respect to the parent nucleus. C. 2 lens to obtain length of the lens is 10cm, find X. an 2 inverted image, 2 2 d. Find the equivalent resistance between P and Q from the figure below, 100 00 100 A 20 52 2 e. State the characteristics required for a material to be used as an effective fuse wire. Q3. a. Define the CGS unit of work 2 b. How is heat lost by convection and radiation prevented in a calorimeter? c. List two common 2 properties of electromagnetic waves 2 d. Draw a labelled diagram of a three-pin socket. 2 e. Define the phenomenon that causes a loud sound when the stem of a vibrating tuning fork is kept pressed on a tabletop. 2 Q4. a. Derive an expression that relate the KE of a body with its momenturn. 2 b. An electrical heater is rated 10OKVA-220V. Calculate the electrical energy c. consumed in its commercial units, if the heater was operated for 2 hours. 2 Draw 2 a diagram to show the use of a lens in the Galilean telescope. d.What are Becquerel rays? Name the phenomenon due to which these rays are emitted. e. When is 2 a body said to be at a, "state of equilibrium? SECTION 2 (ATTEMPT ANY 4 QUESTIONS FROM THIS SECTION) Q5. a. A freely oscillating pendulum is shown below. 3 ldentify the positions at which, the bob i) possess maximum PE. i) PE = KE i) the mechanical energy is conserved. RBK School, Mira Road |ICSE- Std 1 to 10 www.rbkschool.org info@rbkschool.og A 2 B b. A load of 220kg is vertically pulled up by a crane through a height of 16m in 40s. Calculate i) Force acting against gravity. i) Total work done. ii) Horse power of the engine pulling the rope. c. (g=10m/s2,1HP =750W). 3 What is the energy transformation in the process of photosynthesis? Also identfy the energy possessed in the following, i) a shooting arrow. i) water stored in an overhead tank, ii) A guitar string plucked. Q6.a. A uniform metre scale of weight 50gf is balanced at the 40cm mark, whena weight of 100gf is suspended at the Scm mark. Where must a weight of 80gf be suspended to balance the metre scale? 3 b.i) Name the radiations that are electromagnetic. i) What happens to the atomic number when these radiations are emitted? i What is the influence on these radiations when exposed to a magnetic or electric field? 3 c.i) What are nuclear waste? Suggest a suitable way for its safe disposal. 2 i) A stone is whirled around in a circular path by tying it to a strong string with help of your hand. Is the stone moving with uniform acceleration? What kind of force acts on the stone and state its direction. 2 Q7. a. State three factors that determine the quantity of heat produced in a conductor. b.Observe the circuit diagram shown below and obtain the value of the resistor, X. 2.52 3 xQ W - W- I 0.5A 6V ive 62 r 20 122 C. i) Define the quantity measured by the unit, Qm. i)With increase in temperature of metals, what is the effect on the above mentioned quantity of metals? ii) What are non ohmic resistors? Give an example. RBKSchool, Mira Road | ICSE Std 1 to 10 www.rbkschool.org | info@rbkschool.org 3 4 Q8. a. The wavelength of an electromagnetic wave is 80A i) ldentify this wave. i) What is the speed of the wave in air. ii) State one use of the above wave. b. Complete the following ray diagram, if, ie (glass) = 42 3 3 60 30 C.i) Sam is surprised to see the pencil he placed in a beaker of water looks diferent. Name the phenomenonyesponsible for the change and illustrate this change with a ray diagram. 2 iJDraw an i- 5 curve to show the variation of the angle of deviation with the angle of incidence. On the curve, mark the point of minimum deviation. 2 Q9. a. You are required to make a water bath (mix of hot and cold water) of mass 50kg at 45 C, by mixing hot water at 90 C with cold water at 20 C. Calculate the mass of hot water needed. 3 b. i) What do you understand by the term, thermal capacity. State its Sl unit. i) With a forecast of frost, a wise farmer waters his fields. Give suitable reasons. 3 C. Why is a machine not 100% efficient? A pulley system with velocity ratio 4 is used to lift a load of 100kgf through a height of 15m by applying a force of 40kgf. Calculate, i) distance through which effort is applied. i) work done by the effort. i ) efficiency of pulley system. 4 Q10.a. Name the waves used in the process of sound ranging. Justify with one suitable reason. Are these waves audible to us? 3 b. A man standing away from a cliff produces a sound and receives the reflected sound after 0.09s. Calculate i) distance of man from the cliffif speed of sound is 340m/s. Will the man hear a distinct echo? cDefine timbre. State the factor it depends 3 on. 2 i) What are damped vibrations? Name 2 forces that act on a body undergoing damped 2 vibrations. RBKSchool, Mira Road |ICSE - Std1 to 10 www.rbkschool.org info@rbkschool.org 4
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