#neet
- An air bubble in a glass slab with refractive index 1.5 (near normal incidence) is 5 cm deep when viewed from one surface and 3 cm deep when viewed from the opposite face. The thickness (in cm) of the slab is Answer: 2. 12 Apparent depth =real depth/μ . The bubble is at a fixed real depth x from one face and t-x from the other. x/1.5=5⇒ x=7.5 cm;... 1
- The interference pattern is obtained with two coherent light sources of intensity ratio n. In the interference pattern, the ratio I_max-I_minI_max+I_min will be Answer: 1. 2sqrt n/n+1 With intensities I₁:I₂=n (take I₁=nI₂ ), I_max=(√(I₁)+√(I₂))² and I_min=(√(I₁)-√(I₂))² . fracI_max-I_minI_max+I_min=4... 1
- A person can see clearly objects only when they lie between 50 cm and 400 cm from his eyes. In order to increase the maximum distance of distinct vision to infinity, the type and power of the correcting lens, the person has to use, will be Answer: 1. concave, -0.25 diopter The person's far point is 400 cm; to see infinity the lens must form the image of a distant object at 400... 1
- Cotyledon of maize grain is called : Answer: 4. scutellum In maize (a monocot) the single cotyledon is a shield-shaped structure called the scutellum, lying towards one side of... 1
- In the stomach, gastric acid is secreted by the : Answer: 2. parietal cells The parietal (oxyntic) cells of the gastric glands secrete HCl and intrinsic factor. Peptic (chief) cells secrete... 1
- A typical fat molecule is made up of : Answer: 2. One glycerol and three fatty acid molecules A triglyceride (typical fat) is formed by esterification of one glycerol with three f... 1
- Depletion of which gas in the atmosphere can lead to an increased incidence of skin cancers : Answer: 2. Ozone The ozone layer absorbs harmful UV-B radiation. When ozone is depleted, more UV reaches the earth and causes skin cancers a... 1
- Chrysophytes, Euglenoids, Dinoflagellates and Slime moulds are included in the kingdom : Answer: 2. Protista Chrysophytes (diatoms), euglenoids, dinoflagellates, slime moulds and protozoans are unicellular eukaryotes placed in Ki... 1
- Water vapour comes out from the plant leaf through the stomatal opening. Through the same stomatal opening carbon dioxide diffuses into the plant during photosynthesis. Reason out the above statements using one of following options : Answer: 2. Both processes can happen together because the diffusion coefficient of water and CO ₂ is different. Both processes can occur tog... 1
- In mammals, which blood vessel would normally carry largest amount of urea ? Answer: 3. Hepatic Vein Urea is made in the liver, so the blood leaving the liver through the hepatic vein carries the largest amount of ure... 1
- Seed formation without fertilization in flowering plants involves the process of : Answer: 4. Apomixis Formation of seeds without fertilisation is called apomixis, in which the embryo develops from diploid cells of the ovul... 1
- Which of the following is wrongly matched in the given table ?Microbe | Product | Application(1) Trichoderma polysporum | Cyclosporin A | immunosuppressive drug(2) Monascus purpureus | Statins | lowering of blood cholesterol(3) Streptococcus | Strept… Answer: 4. Clostridium butylicum - Lipase - removal of oil stains Clostridium butylicum is used to produce butyric acid. Lipase is obtained... 1
- In a testcross involving F_1 dihybrid flies, more parental-type offspring were produced than the recombinant-type offspring. This indicates : Answer: 3. The two genes are linked and present on the same chromosome. In a testcross with an F₁ dihybrid, independent assortment gives 1:1... 1
- It is much easier for a small animal to run uphill than for a large animal, because : Answer: 2. Smaller animals have a higher metabolic rate. Smaller animals have a larger surface area to volume ratio and so a higher metaboli... 1
- Which of the following is not a characteristic feature during mitosis in somatic cells ? Answer: 4. Synapsis Synapsis (pairing of homologous chromosomes) occurs in prophase I (zygotene) of meiosis, not in mitosis. Spindle fibres,... 1
- Which of the following statements is not correct ? Answer: 1. Pollen grains of many species can germinate on the stigma of a flower, but only one pollen tube of the same species grows into th... 1
- Specialised epidermal cells surrounding the guard cells are called : Answer: 2. Subsidiary cells Epidermal cells around the guard cells, which differ from other epidermal cells, are subsidiary cells. Bulliform... 1
- Which of the following guards the opening of hepatopancreatic duct into the duodenum ? Answer: 4. Sphincter of Oddi The sphincter of Oddi guards the opening of the hepatopancreatic duct into the duodenum. The pyloric sphincter... 1
- Stems modified into flat green organs performing the functions of leaves are known as : Answer: 3. Phylloclades Flat, green stems that do the work of leaves (photosynthesis) are phylloclades, e.g. Opuntia. Cladodes: short stem b... 1
- The primitive prokaryotes responsible for the production of biogas from the dung of ruminant animals, include the : Answer: 3. Methanogens Methanogens are archaebacteria found in the rumen of cattle. They produce methane and are responsible for biogas prod... 1
- A river with an inflow of domestic sewage rich in organic waste may result in : Answer: 4. Death of fish due to lack of oxygen. Sewage rich in organic waste is decomposed by microbes, which use up dissolved oxygen (high... 1
- A cell at telophase stage is observed by a student in a plant brought from the field. He tells his teacher that this cell is not like other cells at telophase stage. There is no formation of cell plate and thus the cell is containing more number of c… Answer: 2. Polyploidy Failure of cell plate formation in telophase (cytokinesis fails) leaves a cell with a doubled chromosome number. Cells... 1
- A solid sphere of mass m and radius R is rotating about its diameter. A solid cylinder of the same mass and same radius is also rotating about its geometrical axis with an angular speed twice that of the sphere. The ratio of their kinetic energies of… Answer: 1. 1 : 5 Rotational kinetic energy is E=1/2 Iω² , so find each moment of inertia first. Sphere about a diameter: I_s=2/5mR² , so E_s... 1
- Analogous structures are a result of : Answer: 2. Convergent evolution Analogous structures have different origins but similar function because unrelated organisms face similar en... 1