Recent questions tagged ch3

An inductor of inductance $ L = 400\: mH$ and resistors of resistances $R1 = 2\Omega$ and $R2 = 2\Omega$ are connected to a battery of $emf\: 12V$ as shown in the figure. The internal resistance of the battery is negligible. The switch $K$ is closed at $t= 0$. The potential drop across $L$ as a function of time is

asked Feb 13, 2014 by thanvigandhi_1

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Let C be the capacitance of a capacitor discharging through a resistor R. Suppose t1 is the time taken for the energy stored in the capacitor to reduce to half its initial value and t2 is the time taken for the charge to reduce to one-fourth its initial value. Then the ratio $ \large\frac{t1}{t2}$ will be

asked Feb 13, 2014 by thanvigandhi_1

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Two resistors R and 2R are connected in series in a circuit. The thermal energy developed in R and 2R are in the ratio

asked Feb 13, 2014 by thanvigandhi_1

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Calculate the charge on the $5\mu F$ capacitor long time after assembling the circuit

asked Feb 10, 2014 by thanvigandhi_1

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$50V$ battery is supplying a current of $10A$ when connected to a resistor. If the efficiency of the battery at this current is 25%, then the internal resistance is:

asked Feb 10, 2014 by thanvigandhi_1

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A capacitor is charged and then made to discharge through a resistance. The time constant is $ \tau$. In what time will the potential difference across the capacitor decrease by 10%

asked Feb 10, 2014 by thanvigandhi_1

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A capacitor $C_1$ of capacitance $1 \mu F$ and $C_2$ of capacitance $ 2 \mu F$ are separately charged by a common battery for a long time. The two capacitors are then separately discharged through equal resistors. Both the discharge circuits are connected at $t=0$. One or more of the following happen.

asked Feb 8, 2014 by thanvigandhi_1

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A capacitor of capacitance $ 500 \mu F$ is connected to a battery through a $10k \Omega $resistor. Then, which of the following are true: \[\] The charge stored on the capacitor in the first $5s$ is larger than the charge stored in the next

asked Feb 8, 2014 by thanvigandhi_1

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In an electric circuit containing a battery, the charge (positive by convention) inside the battery

asked Feb 3, 2014 by thanvigandhi_1

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If $A=\begin{bmatrix}2 & 3\\5 & -2\end{bmatrix}$ then express $A^{-1}$ in terms of $A$

asked Jan 30, 2014 by rvidyagovindarajan_1

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Given $A=\begin{bmatrix} 3 & -3 & 4 \\2 & -3 & 4 \\0 & -1 & 1 \end{bmatrix}$ How can we express $A^{-1}$ in terms of A?

asked Jan 29, 2014 by balaji

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If $A=\begin{bmatrix}2 & sec^{-1}x\\-1 & cosec^{-1} x \end{bmatrix}$ is a singular matrix then find the value of $x$

asked Jan 28, 2014 by rvidyagovindarajan_1

1 answer

1. The theca layer of ovarian follicles is organised into an inner theca interna and an outer theca externa. 2. The primary oocyte within the tertiary follicle grows in size and completes its first meiotic division. 3. First meiotic division is an unequal division resulting in the formation of a large haploid tertiary oocyte and a tiny first polar body Regarding 1,2 and 3 :

asked Jan 6, 2014 by pady_1

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1. Each primary oocyte then gets surrounded by a layer of granulosa cells and is called the primary follicle. 2. The primary follicles get surrounded by more layers of granulosa cells and a new theca and are called secondary follicles. 3. The secondary follicle soon transforms into a tertiary follicle which is characterised by a fluid filled cavity called antrum. Regarding 1,2 and 3 :

asked Jan 6, 2014 by pady_1

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1. Oogonia start division and enter into prophase-II of the meiotic division 2. Oogonia get temporarily arrested at that stage are called primary oocytes. 3. Each primary oocyte then gets surrounded by a layer of granulosa cells and is called the primary follicle. Regarding 1,2 and 3 :

asked Jan 6, 2014 by pady_1

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1. The process of formation of a mature female gamete is called oogenesis. 2. Oogenesis is initiated during puberty when a couple of million gamete mother cells (oogonia) are formed within each mature ovary. 3. More oogonia are formed and added during 18 to 35 years (reproductive period). Regarding 1,2 and 3 :

asked Jan 6, 2014 by pady_1

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1. Sperms released from the seminiferous tubules, are transported by the accessory ducts. 2. Secretions of epididymis, vas deferens, seminal vesicle and prostate are essential for maturation of sperms. 3. Secretions of epididymis, vas deferens, seminal vesicle and prostate are essential for motility of sperms. Regarding 1,2 and 3 :

asked Jan 6, 2014 by pady_1

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The human male ejaculates (i) about 20 to 30 million sperms during a coitus of which, (ii) for normal fertility, at least 40 per cent sperms must have normal shape and size and (iii) for normal fertility, at least 50 per cent of them must show vigorous motility. Regarding (i), (ii) and (iii) :

asked Jan 6, 2014 by pady_1

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1. A plasma membrane envelops the whole body of sperm. 2. The sperm head contains an elongated haploid nucleus. 3. The posterior portion of nucleus is covered by a cap-like structure, acrosome. 4. The acrosome is filled with enzymes that help fertilisation of the ovum. Regarding 1,2,3 and 4 :

asked Jan 6, 2014 by pady_1

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1. The spermatids are transformed into spermatozoa by the process called gametogenesis. 2. After spermiogenesis, sperm heads become embedded in the Leydig cells. 3. And they are finally released from the seminiferous tubules by the process called spermiation. Regarding 1,2 and 3 :

asked Jan 6, 2014 by pady_1

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1. Primary spermatocytes periodically undergo meiosis. 2. A primary spermatocyte completes the first meiotic division leading to formation of four secondary spermatocytes. 3. Secondary spermatocytes undergo the second meiotic division to produce four unequal, haploid spermatids. Regarding 1,2 and 3 :

asked Jan 6, 2014 by pady_1

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1. Each spermatogonium contains 46 chromosomes. 2. Primary spermatocytes have 23 chromosomes each. 3. Secondary spermatocytes also have 23 chromosomes each. Regarding 1,2 and 3 :

asked Jan 6, 2014 by pady_1

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In testis: 1. The immature male germ cells are called spermatogonia (sing. spermatogonium). 2. Spermatogonia produce sperms by spermatogenesis. 3. Spermatogenesis begins at puberty. Regarding 1,2 and 3 :

asked Jan 6, 2014 by pady_1

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1. The alveoli open into mammary tubules. 2. The tubules of each lobe join to form a lactiferous duct. 3. Several lactiferous ducts join to form a wider mammary ampulla 4. Mammary ampulla is connected to mammary duct. Regarding 1,2,3 and 4 :

asked Jan 6, 2014 by pady_1

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1. The glandular tissue of each breast is divided into 5-10 mammary lobes containing clusters of cells called alveoli. 2. The cells of alveoli secrete milk. 3. Milk is stored in the cavities (lumens) of alveoli. Regarding 1,2 and 3 :

asked Jan 6, 2014 by pady_1

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1. Mons pubis is a cushion of fatty tissue covered by skin and pubic hair. 2. The *** minora are fleshy folds of tissue, which extend down from the mons pubis and surround the vaginal opening. 3. The * majora are paired folds of tissue under the *** minora. Regarding 1,2 and 3 :

asked Jan 6, 2014 by pady_1

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1. The uterus opens into ****** through a broad cervix. 2. The cavity of the cervix is called cervical canal. 3. Cervical canal solely forms the birth canal. Regarding 1,2 and 3 :

asked Jan 6, 2014 by pady_1

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1. The infundibulum leads to a wider part of the oviduct called isthmus. 2. The last part of the oviduct is ampulla. 3. Ampulla has a narrow lumen. 4. Isthmus joins the uterus. Regarding 1,2,3 and 4 :

asked Jan 6, 2014 by pady_1

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1. The ovaries are located one on each side of the upper abdomen. 2. Each ovary is about 2 to 4 cm in length 3. They are connected to the pelvic wall and uterus by ligaments. Regarding 1,2 and 3 :

asked Jan 6, 2014 by pady_1

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1. The *** is the male external genitalia 2. It is made up of special tissue that helps in erection of the * 3. Erection of the *** facilitates insemination. Regarding 1,2 and 3 :

asked Jan 6, 2014 by pady_1

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1. The urethra originates from the urinary bladder 2. It extends through the ***** to its external opening 3. Its external opening called urethral meatus. Regarding 1,2 and 3 :

asked Jan 6, 2014 by pady_1

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In testes : 1. Each seminiferous tubule is lined on its inside by two types of cells called male germ cells and Sertoli cells. 2. Sertoli cells undergo meiotic divisions finally leading to sperm formation. 3. The male germ cells provide nutrition to the germ cells. Regarding 1,2 and 3 :

asked Jan 6, 2014 by pady_1

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The male reproductive system : 1. The testes are situated outside the abdominal cavity within a pouch called . 2. The helps in maintaining the high temperature of the testes, 2–2.5o C higher than the normal internal body temperature. 3. 2–2.5o C higher than the normal internal body temperature is necessary for spermatogenesis. Regarding 1,2 and 3 :

asked Jan 6, 2014 by pady_1

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Plant life cycle and alternation of generations: 1. The haploid gametophytic plant body produces gametes by mitosis. 2. Following fertilisation the zygote divides by mitosis to produce a diploid sporophytic plant body. 3. Haploid spores are produced by this plant body by meiosis. Regarding 1,2 and 3:

asked Jan 6, 2014 by pady_1

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1. Double fertilisation is an event unique to angiosperms and gymnosperms. 2. The zygote develops into an embryo 3. Primary endosperm nucleus (PEN) develops into endosperm which provides nourishment to the developing embryo. 4. The synergids and antipodals degenerate after fertilisation. 5. During these events the ovules develop into seeds and the ovaries develop into fruit. Regarding 1,2,3,4 and 5:

asked Jan 6, 2014 by pady_1

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In angiosperm : 1. After pollination, the pollen grains germinate on the stigma and the resulting pollen tubes grow through the tissues of stigma and style and reach the ovule. 2. The pollen tubes enter the embryo-sac where two male gametes are discharged. 3. One of the male gametes fuses with the egg cell to form a zygote (syngamy). 4. The other male gamete fuses with the diploid secondary nucleus to produce the triploid primary endosperm nucleus (PEN). 5. This event is termed as double fertilisation Regarding 1,2,3,4 and 5:

asked Jan 6, 2014 by pady_1

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In flower (of angiosperm) : 1. Each of the cells of an embryo-sac is haploid. 2. Each embryo-sac has a three-celled egg apparatus – one egg cell and two synergids, two antipodal cells and three polar nuclei. 3. The two synergids fuse to produce a diploid secondary nucleus. Regarding 1,2 and 3:

asked Jan 6, 2014 by pady_1

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In flower (of angiosperm) : 1. The anthers, following meiosis, produce pollen grains. 2. The embryo-sac formation preceeds meiosis. 3. Each of the cells of an embryo-sac is haploid. Regarding 1,2 and 3:

asked Jan 6, 2014 by pady_1

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In angiosperms : 1. The pollen grains and ovules are developed in specialised structures called flowers. 2. In angiosperms, the seeds are enclosed by fruits. 3. The angiosperms are an exceptionally large group of plants occurring in wide range of habitats. Regarding 1,2 and 3:

asked Jan 6, 2014 by pady_1

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In gymnosperms : 1. The pollen grain is released from the microsporangium. 2. Pollen grains are carried in air currents and come in contact with the opening of the ovules borne on megasporophylls. 3. The pollen tube carrying the male gametes grows towards archegonia in the ovules and discharge their contents near the mouth of the archegonia. 4. Following fertilisation, zygote develops into an embryo and the ovules into seeds. 5.The seeds are not covered. Regarding 1,2,3,4 and 5:

asked Jan 6, 2014 by pady_1

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In gymnosperms : 1. The megaspore mother cell divides mitotically to form four megaspores. 2. All the four megaspores are enclosed within the megasporangium (nucellus) develop into a multicellular female gametophyte 3. Female gametophyte bears one archegonium or female *** organ. 4. The multicellular female gametophyte is also retained within megasporangium. Regarding 1,2,3 and 4:

asked Jan 6, 2014 by pady_1

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In gymnosperms : 1. The megaspore mother cell is differentiated from few of the cells of the nucellus. 2. The nucellus is protected by envelopes and the composite structure is called an ovule. 3. The ovules are borne on megasporophylls which may be clustered to form the female cones. Regarding 1,2 and 3:

asked Jan 6, 2014 by pady_1

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In gymnosperms : 1. The microspores develop into a male gametophytic generation 2. Male gametophytic generation is highly reduced and is confined to a unicellular form. 3. The reduced gametophyte is called a pollen grain. 4. The development of pollen grains take place outside the microsporangia.

asked Jan 6, 2014 by pady_1

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In gymnosperms : 1. The gymnosperms are heterosporous. 2. They produce diploid microspores and megaspores. 3. The two kinds of spores are produced within sporangia 4. Sporangia are borne on sporophylls which are arranged spirally along an axis to form lax or compact strobili or cones. Regarding 1,2,3 and 4:

asked Jan 6, 2014 by pady_1

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In gymnosperms : 1. The roots are generally tap roots. 2. Roots in some genera have fungal association in the form of mycorrhiza 3. Some others small specialised roots called coralloid roots are associated with N2- fixing cyanobacteria.

asked Jan 6, 2014 by pady_1

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In pteridophytes: 1. The megaspores and microspores germinate and give rise to male and female gametophytes, respectively. 2. The female gametophytes in these plants are retained on the parent sporophytes for variable periods. 3. The development of the zygotes into young embryos take place within the female gametophytes. 4. The development of the zygotes into young embryos within the female gametophytes is a precursor event to the seed habit considered an important step in evolution.

asked Jan 6, 2014 by pady_1

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In pteridophytes: 1.The gametophytes of the pteridophytes bear male and female * organs called archegonia and antheridia, respectively. 2. Water is required for transfer of antherozoids – the male gametes released from male * organ, to the mouth of female *** organ. 3. Fusion of male gamete with the egg result in the formation of zygote. 4. Zygote thereafter produces a multicellular well-differentiated sporophyte 5. Sporophyte is the dominant phase of the pteridophytes.

asked Jan 6, 2014 by pady_1

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In pteridophytes: 1. Pteridophytes are the first terrestrial plants to possess vascular tissues – xylem and phloem. 2. The pteridophytes are found in cool, damp, shady places 3. They can never grow in sandy-soil conditions.

asked Jan 6, 2014 by pady_1

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In Mosses: 1. After fertilisation, the zygote develops into a sporophyte 2. Sporophyte consists of a foot, seta and capsule. 3. The seta contains spores. 4. Spores are formed after mitosis.

asked Jan 6, 2014 by pady_1

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In liverworts: 1. During sexual reproduction, male and female *** organs are produced either on the same or on different thalli. 2. The sporophyte is differentiated into a foot, seta and capsule. 3. After meiosis, spores are produced within the capsule. 4. These spores germinate to form free-living gametophytes.

asked Jan 6, 2014 by pady_1

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