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  1. Prashasti

    Sex linked diseases and lyonization in females

    Suppose, there's a disease "D", which is an X-linked, dominant disease. Now, there's a female who possesses the allele for this disease in one of her two X chromosomes. (XDX) It's easy to say that since the allele for the disease is dominant, she'll suffer from it. Now, it's a well known fact...
  2. Prashasti

    Course of the Optic Nerve

    We had a class on optic nerve today. Our teacher said that the optic nerve "originates" from the retina, and continues up till the commencement of the optic chiasma, and is, approximately, 4 cm long. My question is, Why is it considered to be a cranial nerve when it does not even originate...
  3. Prashasti

    Question related to molarity

    Ammonia gas is passed into water, yielding a solution of density 0.93 g/cm^3 and containing 18.6% NH3 by weight. The mass of NH3 per cc of the solution is 1) 0.17 2) 0.51 3) 0.34 4) 0.68 I solved it using the molarity equation. Molarity = 10xd/MM where, x - % by weight d - density MM -...
  4. Prashasti

    Convex lenses

    Homework Statement A thin double convex lens of focal length f is broken down into two halves at the axis. The two haves are then combined, as shown in the figure. What will be the focal length for the arrangements...
  5. Prashasti

    Relative stability of ortho and para isomers

    Generally, in organic reactions, the para isomer is found to be more stable (as it is symmetrical) because of which it is produced in greater amount than the ortho isomer. However, there are some exceptions also, for example, in some reactions the less sterically hindered ortho isomer is...
  6. Prashasti

    Dipole in an external electric field

    Homework Statement Why isn't the expression for torque on a dipole kept in an external electric field ExP? Why is it PxE? No such indication has been given in any of the derivations, that it is mandatory for it to be PxE, so why can't it be ExP? 2. The attempt at a solution Is it all about...
  7. Prashasti

    Kirchhoff's Loop Rule Problem.

    Homework Statement Actually, the main question is to find out the potential difference between the points 'A' and 'D'. The cell with emf 'E' has not been shown in the main question, but I have assumed it to be connected between 'A' and 'D'. Each resistor is of 1 Ohm. 2. The attempt at a...
  8. Prashasti

    Modulation of waves (Communication Systems)

    Please look at the attachments below. I shall use the word "modulation" instead of "amplitude modulation" since I've been taught about AM only. So, my question is, in the first image (that I've attached), the messenger wave (which is modulated with the high frequency carrier wave) as well as...
  9. Prashasti

    Amplitude Modulation of a wave

    Homework Statement I am utterly confused. When I was reading my textbook , I found something unacceptable. While deriving an expression for a modulated wave, It's been given that "A sinusoidal carrier wave can be represented as c (t) = Ac sin (ωt + Φ) where c (t) is the signal strength of...
  10. Prashasti

    Magnetic field inside a Solenoid

    Homework Statement Can I derive an equation for magnetic field inside a solenoid using the formula for magnetic field on the axis of a current carrying coil? Homework Equations B = μI/2r ( Magnetic field at the centre of a current carrying coil) The Attempt at a Solution B = μI/2r Let the...
  11. Prashasti

    Fraunhofer Diffraction Doubt

    Homework Statement A monochromatic source of light 'S' is placed at the principal focus of a convex lens 'L1'. A parallel beam of light or a plane wave front is incident on the narrow slit represented by AB (its width - 'a') Homework Equations So, what my teacher did was, She showed...
  12. Prashasti

    Young's Double Slit Experiment refraction

    Homework Statement Young's double slit experiment 'd' - Separation between the two slits 'D' - Separation between the double slit and the screen 'S' - Source (Primary) (It is coherent) S1, S2 - Secondary sources Δx - Path difference between the two rays coming out from S1 and S2 Δx° - Path...
  13. Prashasti

    Stability of carbocations and inductive effect

    Which carbocation is more stable? 1) CH3-C+=CH2 2) CH3-CH+-CH3 Basically, I want to know whether the =CH2 group is electron donating or electron withdrawing. Does it show +I effect like alkyl groups? I mean, like in 2) the carbocation will get stabilised due to the electron donating power of...
  14. Prashasti

    Prism Experiment

    What would happen if two triangular prisms are kept side by side , in the same way? I mean, none of them is in an inverted position. Would this arrangement give a wide spectrum of light?
  15. Prashasti

    Spin magnetic moment

    Does an electron really spin about its own axis? If not, what does spin magnetic moment imply? My physics teacher said "Besides the orbital moment, an electron has an intrinsic magnetic moment, it is called the spin magnetic moment, But I hasten to add that it is not as though the electron is...
  16. Prashasti

    Human Immunodeficiency Virus

    Hi, Today our teacher taught us about AIDS, and she said that it has no cure, because every time the genetic material of the virus replicates, it undergoes mutations, and a new type of virus is formed. Because of this, a lot of viruses are formed, each with a different genotype. That is why...
  17. Prashasti

    Average power in series LCR

    Hello! Homework Statement A sinusoidal voltage of peak 283 V and frequency 50 Hz is applied to a series LCR circuit in when R = 3ohm, L is 25.48mH and C is 796 microF. Find the power dissipated in the circuit. The book says, Power = I^2 R Where I = rms current. Now, I = 283/5 \sqrt{2} =...
  18. Prashasti

    Potentiometer circuit for comparison of two resistances

    Question : Figure shows a potentiometer circuit for comparison of two resistances. The balance point with a standard resistor R = 10.0 Ω is found to be 58.3 cm, while that with the unknown resistance X is 68.5 cm. Determine the value of X. Isn't the question wrong? I've searched for it...
  19. Prashasti

    AC applied to a capacitor.

    In a purely capacitive ac circuit, we get, Im = Vm*ω*C, ....(1) Where, Im = Amplitude of the current Vm = Amplitude of the voltage Now, what I think is, We know that in a purely capacitive circuit, voltage lags behind current by a phase difference of ∏/2 rad. So, at any time 't', I =...
  20. Prashasti

    Electric field, Equipotential surfaces

    Question : The top of the atmosphere is at about 400 kV with respect to the surface of the Earth, corresponding to an electric field that decreases with altitude. Near the surface of the Earth, the field is about 100 V/m. Why then we do not get electric shock as we step outside our house into...
  21. Prashasti

    Colloidal Particles and their size

    Suppose we have a cube, of length 1 metre. It is cut in all the three directions so that 8 cubes, each having 0.5 m as its length. Then, these cubes are again subdivided in the same manner to get cubes with length 0.25m and so on. HOW MANY OF THESE SUCCESSIVE SUBDIVISIONS ARE REQUIRED BEFORE...
  22. Prashasti

    Species, concept of pure and impure breeds.

    The definition of species is "a group of organisms that can interbreed with each other". So, how is interbreeding of two dogs of different species, say a german shepherd and a pitbull, possible? And the concept of a "pure" and "impure" breed - how will you explain it? As according to the...
  23. Prashasti

    Resistors in series and current equivalence.

    "Resistors resist the passage of current through them." Then why the current through each resistor same in series combination? Suppose 'I' current is passing through a system of two resistors connected in series. 1. Won't the first resistor - which is directly connected to the positive...
  24. Prashasti

    Coordination number for fcc and NaCl

    Why is the coordination number for fcc 12, but that in NaCl 6? NaCl crystallises in ccp (or fcc) lattice, then how is it possible?
  25. Prashasti

    Dipolar substances and atoms.

    Can an atom be considered as an example of a dipole? It has positive charge in the nucleus and negative charge around it?!
  26. Prashasti

    Atoms and dipolar substances

    Can an atom be considered as an example of a dipole? It has positive charge in the nucleus and negative charge around it. So, can't it act as a dipole?
  27. Prashasti

    Vector properties

    It is well known that a vector can't be divided by a vector, as a direction can't be divided by a direction. Keeping this in mind, I used the equation, v→ = u→+a→t, and wrote it as t = v→ -u→/a→. Now, isn't it wrong to write the equation like this? As , in it, a vector, that is v→ -u→ is being...
  28. Prashasti

    What is Ferroelectricity?

    In the word "Ferroelectricity", why has the word "ferro" been used when it has nothing to do with ferrous or iron?
  29. Prashasti

    Difference between phenotype and morphology

    What is the difference between phenotype and morphology? As far as I know, both the words convey the same meaning, external observable characteristics.
  30. Prashasti

    Lysosomes and Viruses

    Lysosomes help to clean up dead organelles and intruders like viruses. So, can't they be used to produce anti virals?