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  1. J

    Why we can't hear ?

    If sound travels faster in solids than in air then why on closing our ears we cannot hear the sound properly?
  2. J

    Can i get to NASA?

    What is the scope of btech in PHYSICAL SCIENCES from IIST(indian institute of space science and technology)? after that course it is compulsory to work in ISRO for 5 years...(if you get first class) will that be enough to get into NASA?
  3. J

    Number of live viruses

    Ohhhh......i missed that point..... thanks sir.....you was very helpful.....
  4. J

    Help with a limit equation involving tangent

    divide numerator and denominator by x..
  5. J

    Number of live viruses

    Sir, i can't get you ... can you explain a bit more??? you mean that no more viruses reproduce after 5 seconds?
  6. J

    Number of live viruses

    Homework Statement A virus give birth to 2 new virus in each second and life span of each virus is 5 seconds.The process of reproduction is continuous until the death of the virus.Initially there is one newly born virus at time t=0.Find the total number of live viruses just after 10 seconds...
  7. J

    Stuck with a problem in electrochemistry

    thank you sir....... i am getting it now......:smile:
  8. J

    Stuck with a problem in electrochemistry

    Homework Statement A galvanic cell consisting of two silver electrodes,one in a saturated solution of AgBr and the other in a saturated solution of Ag2CrO4 is prepared.Calculate the value of Ecell at 298K Given Ksp(AgBr) = 5x10-13 M2 and Ksp(Ag2CrO4)=2.4x10-12M3 Homework Equations to...
  9. J

    Function of salt bridge

    What is the function of salt bridge in a daniell cell?Why KNO3 is used in salt bridge ?
  10. J

    Interior angles of a regular polygon

    The number of sides of two regular polygons are in the ratio 5:4 and the difference between their interior angles is 6 degrees.Find the number of sides of the two polygons. I forgot the relation between interior angles and the number of sides of a regular polygon.Can anyone help me to figure...
  11. J

    De morgan's laws

    In my textbook, the proof for demorgan's law, (AintersectionB)* = A*unionB* [*=complement] starts with,saying that for all x belongs to (AintersectionB)* , x is not a member of AunionB. But how can we say that, for example, if A = {1,2,3} and B = (2,3,4,5} and U = {1,2,3,4,5}...
  12. J

    How the charges are transferred?

    why does that happen or how does that happen ?
  13. J

    How the charges are transferred?

    "When we touch a pith ball with an electrified plastic rod, some of the negative charges on the rod are transferred to the pith ball and it also gets charged." I want to know how does this happen ?
  14. J

    How to get back my curiosity

    I'm afraid whether this place is best to post my question.But i need a help as soon as possible.At first,i was very curious to know things or to investigate more about the world. Studying was not at all a burden for me. It was almost a spontanoeus process that i used to read books and i didn't...
  15. J

    Isolated system

    "The charge of an isolated system is conserved" What is the meaning of isolated system ?
  16. J

    Electromagnetic waves

    When we heat a metal, the positive kernels begins to vibrate.Will this vibrations produce electromagnetic waves ?
  17. J

    Can we accelerate in space ?

    How it can be accelerated without an external force ?
  18. J

    Can we accelerate in space ?

    Imagine we are in a space craft which is moving with a constant velocity in empty space. If we are not influenced by any gravitational forces, and if we restart the engine, will it be accelerated ?
  19. J

    What is the physical significance of work?

    As the title suggests, what is work? Or, what is the physical significance of work? My textbook define work as crossproduct of force and displacement. But why do we need that quantity?
  20. J

    How torque, t = r x F ?

    yeah, but why torque is defined as rXF ?
  21. J

    How torque, t = r x F ?

    how torque, t = r x F ? Or, what is the physical meaning of cross product of two vectors?
  22. J

    Distribution of charges

    When a charge is given to a metallic sphere it spreads in its entire surface area,and when a charge is given to an insulating sphere, it spreads over its entire volume.Why is it so?
  23. J

    Masses of fundamental particles

    How were the masses of fundamental particles(electrons,protons,neutrons) determined?
  24. J

    Charge leaks out?

    What is the meaning of the statement "charge leaks out"?Or how charge leaks out? As charge is a property, how can we say that a property leaks out?
  25. J

    Absence of an electron at a point creates a positive charge

    I can't understand how does the absence of an electron at a point creates a positive charge there. In my opinion, it is wrong on account of conservation of charge. Because if we consider an electron(at a point A) as a system, and if the electron get displaced to another point B(in the system)...
  26. J

    Exam question

    Why my answer is incorrect?
  27. J

    Exam question

    Q:Prove that a square matrix A is invertible iff A is non singular. My Ans: Since the inverse of a square matrix is given by, A^ = (1/|A|)adj.A (Where A^ is A inverse) If |A|=0, A^ is not defined. i.e, A^ exist only if A is non singular. In other words, a square matrix...
  28. J

    Unit cell

    Q.The unit cube length of LiCl (NaCl structure) is 5.14 amstrong . Assuming anion-anion contact, calculate the ionic radius for chloride ion. How to assume anion-anion contact ? Can any one help with a 3D figure?
  29. J

    Big bang

    I am having problem with understanding the concept of big bang theory. Actually I don't believe in the theory. How can we say that this universe was formed because of a big explosion? We can't answer the question what happened before that.
  30. J

    What is electrostatic potential

    I didn't understand the first paragraph.What is a curl?"electric field are curl free" what is the physical meaning of this statement? Still I have a large number of doubts in this topic(electrostatics & current)..may be because i am not perfect with the concepts..here are my doubts...
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