• We need your support!

    We are currently struggling to cover the operational costs of Xtremepapers, as a result we might have to shut this website down. Please donate if we have helped you and help make a difference in other students' lives!
    Click here to Donate Now (View Announcement)

Search results

  1. S

    Physics Paper 5 tips

    The scale has already been given on the paper, so each small millimeter box on the y axis is equivalent to 0.2/10 = 0.02, and since the smallest uncertainty is about 0.005, that's about a fourth of a millimeter on either side of the point. So the uncertainty is really, really small, and it's...
  2. S

    Chemistry Paper 4-theory- doubts =D

    For the second row, for the value of [CH3OH], look at the stoichiometric equation; for every mole of CH3CHO used up in the reaction, two moles of CH3OH will be used up. Therefore if the volume remains constant, the concentration can be written in proportion to the number of moles of each...
  3. S

    Chemistry Paper 4-theory- doubts =D

    If it is the one where you have to state the units of the rate constant, then: The units of rate of reaction mol dm^-3 s^-1. The reaction is first order with respect to each reactant involved, so to ensure that the units on the left of the equation are equal to the units on the right side...
  4. S

    Chemistry: Post your doubts here!

    Think of the reaction in this way; replace all the Silicon with Carbon atoms and Chlorine atoms with Hydrogen atoms (only to visualize the reaction, not to do it in reality!) so that you get a structure that is equivalent to ethane, with 1 "C-C" bond and 6 "C-H" bonds. They are basically asking...
  5. S

    Physics: Post your doubts here!

    I'm sorry, I didn't really understand, but electromagnetic waves are not disturbances of air particles or any medium surrounding them; these waves are composed of oscillating electric and magnetic fields, that oscillate perpendicular to the direction of motion; they're not disturbances of the...
  6. S

    ---> Physics Paper 4 Past Paper Discussion <---

    The capacitance of the sphere, as calculated in the previous part of the same question, is 7 * 10^-11 Farads. When the capacitor discharges, the energy stored in the sphere decrease to 25 % of the original, so the final energy is 1/4th of the initial energy: 0.5 * C * V(final)^2 = 0.5 * C *...
  7. S

    ---> Physics Paper 4 Past Paper Discussion <---

    If the gain is infinite, as is expected of an ideal op amp, then even a difference of 10^-15 (it's just a random value!) will result in an infinite output, since anything (except zero) times infinity is equal to infinity, and since an infinite output voltage is impossible, the op amp will be...
  8. S

    ---> Physics Paper 4 Past Paper Discussion <---

    It is given in the question that turning on the direct current of 2.6 Amperes increases the reading on the scale by 2.3 grams, here's the exact paragraph: The wire XY is horizontal and normal to the magnetic field. The length of wire between the poles is 4.4 cm. A direct current of magnitude...
  9. S

    ---> Physics Paper 4 Past Paper Discussion <---

    The question mentions an ideal op amp is being used - one of the main characteristics of an ideal op amp is that it has an infinite open loop gain (this means that when there is no feedback, like in this question, the op amp will always be saturated unless the input voltage is zero), so this op...
  10. S

    ---> Physics Paper 4 Past Paper Discussion <---

    6 c) If the r.m.s. current is equal to 2.6 Amperes, the power dissipated in any components in the circuit will be the same, but the actual maximum curent will not be 2.6 Amperes - if the rms current is equal to 2.6 amperes, the maximum possible current will be 2.3 * sqrt(2) = 3.25...
  11. S

    ---> Physics Paper 4 Past Paper Discussion <---

    Just two points to note (unless it was just the damping you wanted to illustrate, in which case the diagram should be just fine): i) The graph should start at the same point; the original diagram shows the mass initially displaced by 1.5 cm downwards (-1.5 cm) and the question where you are...
  12. S

    ---> Physics Paper 4 Past Paper Discussion <---

    Also, this link: http://answers.yahoo.com/question/index;_ylt=AoKpf_Bkm5nzJa0WVz7yGIwjzKIX;_ylv=3?qid=20100409093730AAgc8FR Good Luck for all your exams!
  13. S

    ---> Physics Paper 4 Past Paper Discussion <---

    Okay, so for a (ii), the basic statement is that both charges have the same sign, or the same polarity. If both the charges have the same sign, they will both affect a charged particle in the same way, they will either both attract or both repel. Taking a look at the graph, there is a point...
  14. S

    ---> Physics Paper 4 Past Paper Discussion <---

    Yahoo Answers is such a savior - I was doubting that statement right after I made it, but see if this explanation helps out: http://answers.yahoo.com/question/index?qid=20120131161711AAekKKO Think of it in this way - suppose the electron was being brought towards the two particles on the...
  15. S

    ---> Physics Paper 4 Past Paper Discussion <---

    Sorry, man, but i'll try to answer both as soon as possible, have to go and revise for other exams too. (BTW even i'm confused with question 4 w_11, I think the following link should be helpful: http://www.physicsclassroom.com/Class/estatics/u8l4d.cfm)
  16. S

    ---> Physics Paper 4 Past Paper Discussion <---

    Since the carrier wave is amplitude modulated with the information signal, the carrier wave will have an "envelope" that joins the crests of each wavelet on the carrier signal. The wavelength of the carrier wave is from one crest on this envelope to the next. On the graph you can see that the...
  17. S

    ---> Physics Paper 4 Past Paper Discussion <---

    The input potential to the inverting input of the op amp is the potential across resistor P, not across the thermistor T - the potential across T is the number of Volts lost when unit charge travels through T, and the potential into the inverting input is the remaining potential, which is the...
  18. S

    ---> Physics Paper 4 Past Paper Discussion <---

    Man, man , i'm sorry, there may not be any force on a stationary electron at that point and the net field strength may be zero, but the potential definitely isn't zero, man, i'm really sorry about that, Ashique was absolutely right - the potential energy of an electron in between the two...
  19. S

    ---> Physics Paper 4 Past Paper Discussion <---

    I'm pretty sure you wrote it right earlier but I answered the wrong question... silly me! Anyways, here's the solution: The mass is undergoing circular motion at the bottom of the path. At this time, there are two forces acting on it, its weight and the tension in the rope. For the mass to...
View older results
Top