NEET UG
- A light rod of length l has two masses m_1 and m_2 attached to its two ends. The moment of inertia of the system about an axis perpendicular to the rod and passing through the centre of mass is Answer: 4. m₁m₂/m₁+m₂l² Take the two masses at distances x₁ and x₂ from the centre of mass, with x₁+x₂=l and m₁x₁=m₂x₂ . This gives x₁=m₂ l/... 1
- One mole of an ideal monatomic gas undergoes a process described by the equation PV^3 = constant. The heat capacity of the gas during this process is Answer: 3. R For a polytropic process PV^x= const, molar heat capacity is C=C_v+R/1-x . Monatomic gas: C_v=3/2R ; here x=3 . C=3/2R+R/1-3=3/... 1
- The temperature inside a refrigerator is t_2°C and the room temperature is t_1°C. The amount of heat delivered to the room for each joule of electrical energy consumed ideally will be Answer: 1. t₁+273/t₁-t₂ The refrigerator works as a heat pump. Ideally its coefficient of performance for the heat delivered to the room is... 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
- 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 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
- 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
- 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
- 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
- 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
- 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
- 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
- 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
- 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 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
- 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
- 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
- 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
- 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
- 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
- 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
- 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
- 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
- Which one of the following statements is wrong ? Answer: 4. Glycine is a sulphur containing amino acid. Glycine is the simplest amino acid, with H as its R group, and has no sulphur. The su... 1