SAFE HANDS NEET - IB - PT4 Date : 25/12/2017 TEST ID: 4 Time : 01:30:00 Marks : th PCB

Transcription

1 SAFE HANDS NEET - IB - PT4 Date : 25/12/2017 TEST ID: 4 Time : 01:30:00 Marks : th PCB PHYSICS 1) b 2) d 3) b 4) c 5) b 6) c 7) c 8) d 9) b 10) a 11) c 12) a 13) b 14) c 15) b CHEMISTRY 16) c 17) d 18) c 19) b 20) d 21) c 22) a 23) c 24) a 25) c 26) a 27) a 28) a 29) c 30) c : ANSWER KEY : 46) c 47) c 48) a 49) d 50) a 51) a 52) d 53) a 54) a 55) d 56) d 57) c 58) b 59) c 60) d BIOLOGY 31) a 32) c 33) b 34) d 35) c 36) a 37) c 38) b 39) a 40) b 41) d 42) c 43) c 44) b 45) b P a g e 5

2 SAFE HANDS NEET - IB - PT4 Date : 25/12/2017 TEST ID: 4 Time : 01:30:00 Marks : th PCB Single Correct Answer Type 1 (b) : HINTS AND SOLUTIONS : PHYSICS ubstituti g we get 3 (b) Weight of body at height above the earth s surface is 8 (d) 9 (b) 4 (c) Gravitational field due to a spherical shell At a point inside the shell, The gravitational force acting on a point mass at a distance is 10 (a) For, we get, also 11 (c) lies between and Force = weight suspended + weight of wire of 5 (b) Gravitational force provides the required centripetal force 12 (a) Stress = 6 (c) 13 (b) So, 7 (c) Work done (i) P a g e 6

3 (ii) So, length of wire when tension is 9 N ( change in length) 9 = Hence, final length = = elongation of the wire d = diameter of the wire substituting the values, we get 14 (c) or Therefore, strain produced in the two wires will be in the ratio 1:2. 15 (b) Where L = length of the wire CHEMISTRY Single Correct Answer Type 16 (c) An increase in temperature will change. Addition of inert gas has no effect in Also increase in pressure has no effect if. 17 (d) a Given, Now, 18 (c) log [ ] [ ] [ ][ ] [ ], +ve for the reaction, 19 (b) a salt gives strong base and weak acid on dissolving in water. Hence, it produces an alkaline solution. a 20 (d) a Strong base Weak acid It is the characteristic of reaction. 21 (c) solution is also present there which also undergoes self ionisation. at If it is taken simply even without common ion effect, higher concentration must be considered which is but from HCl decreases self ionisation which further decreases self ionisation, hence [ ]from. Hence, net concentration must be smaller than M. 22 (a) og og [ ] og og On solving, 23 (c) Among the given species, correct order of increasing acidic, strength is P a g e 7

4 is a basic (i.e., it tends to gain a proton) and hence is least acidic. is neutral species. is most acidic as it readily lose proton. 24 (a) 25 (c) Equal equivalent of species react together. 26 (a) r r e e 27 (a) e Thus, is oxidized. 28 (a) i i Oxidation number of hydrogen is decreasing from 0 to So, is acting as oxidising agent in this reaction. 29 (c) b b b 30 (c) BIOLOGY Single Correct Answer Type 31 (a) The M-phase represents the phase when the actual cell division or mitosis occurs and the interphase represents the phase between two successive M-phases. It is significant to note that in the 24 hour average duration of cell cycle of a human cell, cell division proper lasts for only about an hour. The interphase lasts more than 95% of the duration of cell cycle 32 (c) During anaphase stage of mitosis, centromere of the chromosome divides and the two chromatids start repelling each other, separate completely to become daughter chromosome and move towards the opposite poles. 33 (b) The interphase takes approximate 75-95% of the entire generation time 34 (d) The interphase, as called the resting phase, is the time during which the cell is preparing for division by undergoing both cell growth and DNA replication. It is the phase between two successive M-phases The interphase is divided into three further classes -phase (Gap 1), S-phase (synthesis) and - phase (Gap 2) 35 (c) Anaphase is characterised by splitting of the centromeres and separation of chromatids. Chromatids move to opposite poles from the equatorial plates. 36 (a) Kinetochores serve as the sites of attachment of spindle fibres to the chromosomes that are moved into position at the centre of the cell. 37 (c) -phase or second gap phase is the gap between DNA synthesis and division. This particular phase is spent in synthesizing molecules other than DNA, which are required for cell division. 38 (b) Replication of DNA takes place at S-phase of cell cycle. The number of chromosomes reduced only in meiosis. So, the number remain 14, 14, and 14 in after S and after M-phase. 39 (a) M cdk cyclin activates anaphase promoting complex. 40 (b) During meiosis, four haploid cells are produced by reductional division from a single diploid cell. Parent cell contains replicated chromosomes, but the daughter cells contains unreplicated chromosomes P a g e 8

5 41 (d) The difference between the diffusion pressure of the solution and its solvents at a particular temperature and atmospheric conditions is called DPD (Diffusion Pressure Deficit). DPD is also known as suction pressure. In fully turgid cells, turgor pressure is equal to osmotic pressure and hence diffusion pressure deficit becomes zero in such case. OP=TP(in turgid cell) DPD= 0(zero) 42 (c) Transport of water soluble substances (glucose, sodium ions and chloride ions) is facilitated by transport proteins. The transport proteins are embedded in the lipid bilayer of cellular membranes and provide sites at which such molecules cross the membrane The transport proteins themselves do not create a concentration gradient. A concentration gradient must already be present in order to facilitate diffusion. A transport protein simply provides a binding site that binds the specific molecule ( glucose) or ion to be transported After binding the specific molecule, the transport protein changes its shape and carries the molecule across the membrane where it releases the molecule. The transport protein returns to its original shape and waits to catch another molecule to be transported 43 (c) When a cell is placed in hypertonic solution, the protoplasm shrinks and leaves the cell wall due to exosmosis and cell becomes failed. The space between plasma membrane and cell wall of plasmolyzed cell is occupied by hypertonic solution. 44 (b) ABA (abscisic acid) causes stomata to close by inhibibition of an ATP dependent pump in the plasma membrane of guard cells. The application of exogenous ABA on leaves of normal plants causes closing of stomata within a few minutes. ABA acts in the presence of, which decreases the ph of guard cells. ABA includes the loss of ions, which decreases the osmotic concentration of guard cells as compared to adjacent epidermal cells. This causes exosmosis and turgidity of guard cell decreases. 45 (b) Xylem sap is composed of minerals and water and is not driven by higher concentration of sugars, while rapid flow of water does not affect the conducting tissue and only the rate of transpiration is increased 46 (c) Very few plants are able to send their roots upto the fringe of water table because of the absence of air. However, phreatophytes are those plant, which can send and absorb the water from water table,., populus deltoides, tamarik, etc. 47 (c) A trichome is initiated as a protuberance from an epidermal cell. Generally, a dense covering of woody trichomes controls the rate of transpiration. They also reduce the heating effect of sunlight. They aid in the protection of plant body from outer injurious agencies. 48 (a) Pea seeds contain protein, while wheat contains starch, the imbibition capacity of proteins is more than that of starch. That is why, pea seeds imbibe more water and show more swelling than those of wheat grains. 49 (d) Process of diffusion is actively involved in various processes of life like transpiration by plants, respiration in livings and photosynthesis. It is a part of all the three processes 50 (a) Movement of water through cell wall is apoplastic. 51 (a) Insectivorous plants grows in the soil, which have poor amount of nitrogen contents (nitrate). Nitrogen is very essential for metabolism. To solve this problem, these plants kill and digest insects for their nitrogen contents, e.g., Nepenthes. 52 (d) The macronutrients includes carbon, hydrogen, oxygen, nitrogen, phosphorus, sulphur, potassium, calcium and magnesium 53 (a) Nitrogen is mainly absorbed in the form of nitrate from soil P a g e 9

6 54 (a) Hydroponics were first demonstrated in the year (d) g is an activator of ribulose bisphosphate carboxylase oxygenase and phosphoenol pyruvate carboxylase 56 (d) Plants requires purified water and mineral nutrient salts for their growth 57 (c) The environment in hydroponics greenhouse is tightly controlled for maximum efficiency and this new mind set is called CEA (Controlled Environment Agriculture) 58 (b) For the uptake of ions in the second phase, the pathway followed is called active uptake 59 (c) Some plant species accumulate selenium, some others gold, while some plants growing near nuclear test sites take up radioactive strontium 60 (d) Soilless culture helps in knowing the essentially of an element as well as the diseases it may cause due to its deficiency and the toxicity caused by an element P a g e 10