Lovely Public Sr. Sec. SchoolRevision Test – Science – XII

Duration – 3 Hrs. M.Marks: 100(Chemistry – 30 Marks)

1. How does white phosphorus differ from red phosphorus structurally? 1 2. Indicate the steps in the preparation of potassium dichromate from chromite ore (FeCr2O4). What is the effect of increasing pH on its solution? 23. Give the IUPAC name of [Fe(ox)3 ]--3 .What type of isomerism does it show ?Draw the structures of isomers. 2 4. Specify the oxidation state and coordination number of the central metal ion in Co(H2O)4(NO2)2]Cl. What type of isomerism does it show? Write IUPAC name of its isomer. 25. (i)What are vitamins ?How are they classified ?Give an example of each type.(i) Why vitamin C and B group vitamins must be supplied regularly in diet ? 3

6.(i)What is the difference between a nucleoside and a nucleotide ?(ii) What are nucleic acids ? Mention an important function of RNA. (iii) Two strands of DNA molecule are complementary to each other. Explain. 37.Differentiate : (i) mineral and ore (ii) roasting and calcination (iii) cast iron and pig iron 3 8.Account for the following : (i) transition metals generally form coloured compounds.(ii) enthalpies of atomisation of transition metals are high.(iii) transition metals and their many compounds act as good catalyst. 3 9.Explain (i) Tranquilizer (ii) Antibiotic (iii) Antihistamine 310.Write the name and structure of the monomer(s) of : (i) Dacron (terylene) (ii) Teflon (iii) Buna – N 311.(i)Give reason : (a) Noble gases have large positive values of electron gain enthalpy.(b) Ozone acts as a powerful oxidising agent.(ii) Write balanced equations for the following :(a)NaCl is heated with sulphuric acid in presence of MnO2.(b)Chlorine gas is passed into aqueous NaI solution.(iii) Give the structure and shape of oleum (H2S2O7). 5

(Physics – 30 Marks)Q12. State Huygens principle and use it to construct refracted wave front for refraction of a plane wave front at a plane refractive surface. Hence derive Snell’s law. (3)Q13(a )What is the de-Broglie wave length of a 10 Kg object moving with a speed of 2m/s?(b) Draw a graph showing the variation of photoelectric current with collector plate potential for two equal frequencies, v1 =v2, of incident radiation having the different intensity. In which case will the stopping potential be higher? (3)Q.14 A lens is made of flint glass refractive index = 1.5, when the lens is immersed in liquid of refractive index 1.25, find the focal length of the lens. (3)Q15 Derive lens maker’s formula for convex lens. (3)Q16 (a) Draw wave fronts before and after refraction from convex lens, when the point source is kept at focus of the lens.(b)Differentiate between ray and wave front. ( c )What is the limit of resolution in optical device. (3)Q17 what is diffraction of light? Draw a graph showing the variation of intensity with angle in a single slit diffraction experiment. Write one feature which distinguishes the observed pattern from the double slit interference pattern. How would the diffraction pattern of a single slit be affected when:

(i) The width of the slit is decreased?(ii) The monochromatic source of light is replaced by a source of white light? (5)

A

BC

Q18. surface of radius of curvature R and of refractive index µ2 and is placed in a refractive index µ1 , where µ1 <µ2 .The surface produces a real image of an object kept in front of it .Using appropriate A spherical assumptions and sign convention ,derive a relationship between the object distance ,image distance ,R, µ1 and µ2 .Under what conditions this surface diverge a ray incident on it. (5)Q19. Explain the working of C E amplifier with circuit diagram. (5) Write the truth table for the gate shown below.

MATHS –(40 MARKS)

Q.20. A director of a selection committee is biased so that he is likely to select his known persons for a job 2 times as likely as others. If there are two posts for a job, find the probability distribution for selection of his relatives. Is director’s act reasonable ? which type of values does he demonstrate here? Is this good for the future? 5

Q21. Find the point on the curve y2=4 x which is nearest to the point (2,-8). 5

Q.22. . Evaluate :∫0

π2

sin2 xsin x+cos x

dx . 5

Q23. A factory has three plants A,b and c. their daily production is 500,1000 and 2000 units. Out of there 0.5% , 0/8% and 1% units respectively are found to be defective. An item is chosen at random and is found to be defective. What is the probability it comes from plant A? 5

Q24. A manufacturer considers that men and women workers are equally efficient and so he pays them at the same rate. He has 30 and 17 units of workers (male and female) and capital respectively, which he uses to produce two types of goods A and B. To produce one unit Of A,2 workers and 3 units of capital are required while 3 workers and 1 unit of capital is required to produce one unit of B, if A and B are priced at Rs. 100 and Rs. 120 per unit respectively , how should be use his resources to maximise the total revenue? Form the above as a LPP and solve graphically. 5

Q25.Two cards are drawn simultaneously (or successively without replacement) from a well shuffled pack of 52 cards. Find the mean and variance of the number of red cards. 5

Q26. Show that if all the rectangles inscribed in a given circle, the square has the maximum area. 5

Q27.An aeroplane can carry a maximum of 200 passengers. A profit of Rs.400 is made on each fist class ticket and a profit of Rs.300 is made on each second class ticket. The airline reserves at least 20 seats for fist class. However ,at least four times as many passengers prefer to travel by second class than by fist class. Determine how many tickets of each type must be sold to maximise profit for the airline. From an LPP and solve it graphically. 5