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## #1 2014-03-29 19:06:13

Agnishom
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From: Riemann Sphere
Registered: 2011-01-29
Posts: 20,684
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### 'Not So Easy Questions' - Part 2 (Science)

Time - 1 hr

***************************************
Section A (Each Question carries 2 marks)

1. A stone dropped from the top of a tower of height 300m high splashed into the water of a pond near the base of the tower. When is the splash heard at the top given that the speed of sound in air is 340 ms[sup]-1[/sup]? (Assume g = 9.8 ms[sup]-2[/sup])

2. What is the frequency of current in each case a) and b) drawn below?

3. A tank is filled with water to a height of 12.5 cm. The apparent depth of a needle lying at the bottom of the tank is measured by a microscope to be 9.4 cm. What is the refractive index of water? If water is replaced by a liquid of refractive index 1.63 cm upto the same height, by what distance would the microscope have to be moved to focus on the needle again?

4. A convex lens of focal length 10 cm is placed coaxially 5 cm away from a concave lend of focal length 10 cm, if an object is placed 30 cm in front of convex lens find the position of the final image formed by the combined system.

5. A wire of resistance R is cut into 5 equal parts. 3 of them are connected parallely and 2 in series. If the equivalent resistance of this combination is R', then calculate the ratio between R and R'.

6. a) What is the relationship between the following molecules?

b) What is the structure of ethyl formate?

c) Give the IUPAC name of the structure below.

7. The valence electrons of the elements A, B, C are given below:

A has 7 valence electrons
B has 6 valence electrons
C has 1 valence electron

Study and answer the following questions:
a) State whether A is a metal or non-metal
b) State whether B is more reactive or less reactive than A.
c) Which group in the periodic table will B belong to?
d) What type of bond will be formed between A and B?

8. A Flask contains 4.4g of CO[sub]2[/sub] gas. Calculate

a) How many molecules of CO[sub]2[/sub] are present in the sample?

b) How many atoms of oxygen are present in the sample?

(Atomic Mass of C is 12 u and that of O is 16 u)

9. You are given a sample of sodim carbonate and napthalene in two seperate beakers. Compare the following with suitable reasons

i) Strength of forces between constituent elements.
ii) Solubility of compounds in water.

10. Explain how the following metal is obtained from their compounds by the reduction process: Metal M which is in the middle of the reactivity series. Give Schematic Representation Only.

11. a) Give the importance of Cristae in Mitochondria.

b) In many plant cells, the nucleus and other cell organelles are pushed near the boundary walls. Why?

12. What are the scientific names for the following receptor in humans:
Receptors of smell, taste, vision, hearing.

13. What happens to glucose that enters the nephron along with the filtrate?

14. Why does a doctor advice use of iodised salts in our diet?

15. What is the cause of muscle cramps and fatigue?

************************************************************
Section B (Each Question carry 1 mark)

1. Anything that influences the valence electrons will affect the chemistry of the element. Which one of the following factors does not affect the valence shell?
(a) Number of Orbits
(b) Nuclear Charge (Z)
(c) Nuclear Mass
(d) Number of core electrons.

2. When we start heating a mixture of sulphur powder and iron fillings, we would observe that:
(a) Sulphur starts melting
(b) Iron Fillings start Melting
(c) Mixture becomes red hot
(d) Mixture evaporates

3. 10 ml of freshly prepared iron sulphate was taken in 4 test tubes. Strips of copper, iron, zinc and aluminium were introduced, each metal in a different test tube. A black residue was obtained in two of them. The right pair of metals forming the precipitates is:
(a) Cu and Zn
(b) Al and Cu
(c) Fe and Al
(d) Zn and Al

4. The color of NO[sub]2[/sub] and PbO formed when lead nitrate is heated are:
(a) Brown and Green
(b) Brown and Yellow
(c) Brown and Colorless
(d) Colorless and Yellow

5. Bottle A contains oxalic acis and Bottle B contains sodium carbonate solution. When pH paper is dipped in each of the solutions, the color seen in A and B will respectively be:
(a) Orange, Blue
(b) Blue, Orange
(c) Green, Blue
(d) Orange, Green

6. Solutions of four metals A, B, C, D were taken. When A was added to B a precipatate of B was formed. When D was added to A, A formed a precipitate. When C was added to D, D formed a precipitate. Which of the following shows the correct order of the metals in decreasing order of their reactivity?
(a) A>B>C>D
(b) C>D>A>B
(c) B>C>D>A
(d) D>C>A>B

7. Which of the following contains the most number of molecules? (Atomic mass of H = 1 amu, S= 32 amu, O = 16 amu, C = 12 amu)
(a) 1 gm of H[sub]2[/sub]S
(b) 1 gm of H[sub]2[/sub]
(c) 1 gm of H[sub]2[/sub]O
(d) 1 gm of CH[sub]4[/sub]

8. You are viewing a prepared slide of striped muscle fibres form math leg. When you focus the microscope, the striations appeared pale and indistinct. To make the striations clearly visible, you would:
(a) Slowly close the diaphragm to reduce the light
(b) Remove the mirror to cut out light.
(c) Change the eye piece to incease magnification
(d) Replace the objective to decrease magnification

9. A student weighed 108 raisins and designated the weight as A. She then soaked them in 50 mL distilled water in a beaker. After 2 hrs, she removed the raisins, wiped them dry from outside and weighed again and called the weight B. For determining the percentage of water absorbed by raisins, she should calculate:
(a)

(b)

(c)

(d)

10. To observe starch granules in potato under a microscope, freshly cut surface of potato was pressed on a slide. The stain that will show starch granules clearly is
(a) Methylene Blue
(b) Iodine
(c) Safranine
(d) Eosine

11. A part of destarched leaf of a potted plant was covered with black paper strips on both sides and the plant was kept in sunlight for 8 hours. The leaf was then tested with iodine after boiling it in alcohol. Only the uncovered part of the leaf turned blue black. The inference is that
(a) CO[sub]2[/sub] is necessary for photosynthesis
(b) Light is necessary for photosynthesis
(c) Chlorophyll is necessary for photosynthesis
(d) Water is necessary for Photosynthesis

12. Student A, B, and C were given five raisins each of equal weight. The raisins were soaked in distilled water at room temperature. A removed the raisins after 30 minues, B after 2 hours and C after one hour. If PA, PB and PC denote percentage absorption of water obtained by students A, B and C respectively, Then
(a) PA > PB > PC
(b) PA < PB < PC
(c) PA < PB > PC
(d) PA = PB = PC

13. Out of the following diagrams, which one depicts a stage in binary fission of Amoeba?

(a) A
(b) B
(c) C
(d) D

14. A ray of light in a glass slab is incident on the interface between the slab and another medium X. The angle of incidence is 30° and the angle of refraction is y where sin(y) = 5/8. If the absolute refractive index of glass is 1.5 and speed of light in vacuum is 3 × 10[sup]8[/sup] m/s, What is the speed of light in medium X?
(a) 3 × 10[sup]8[/sup] m/s
(b) 2.5 × 10[sup]8[/sup] m/s
(c) 1.8 × 10[sup]8[/sup] m/s
(d) 1.2 × 10[sup]8[/sup] m/s

15. A man standing in front of a special mirror finds his image having a very small head and a fat lower portion. What are the shapes of the two parts of the special mirror?
(a) Plane and Convex
(b) Concave and Convex
(c) Convex and Concave
(d) Concave and Plane

16. Resistance of the given wire is R= 3 ohms. The wire is streched by twice its length. The new resistance of the wire is
(a) 18 ohms
(b) 9 ohms
(c) 6 ohms
(d) 40 ohms

17. Current I enters the circuit with R1 and R2 resistances parallel to each other in the ratio 1:3, if R2 =10 ohms, R1 =?
(a) 10 ohms
(b) 20 ohms
(c) 30 ohms
(d) 40 ohms

18. Two lamps, one rated 100 W at 220 V, and the other 60 W at 220 V are connected in parallel to electric mains supply. What currrent is drawn from the line if the supply voltage is 220 V?
(a) 0.727 A
(b) 0.00727 A
(c) 7.227 A
(d) 0.0727 A

19. Which is the source producing alternating current?
(a) Bicycle Dynamos
(b) Dry Cell
(c) Car battery
(d) Electric Motor

20. The distance between 2 alternate compressions is 5m and the time taken to cover it is 10 seconds. The velocity of the wave is
(a) 10.5 m/s
(b) 11.5 m/s
(c) 12.5 m/s
(d) 15 m/s

'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'
'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'
'You have made another human being happy. There is no greater accomplishment.' -bobbym

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## #2 2014-08-13 00:42:16

Olinguito
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Registered: 2014-08-12
Posts: 647

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