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  1. M

    Simple electronic

    hi That's the question. I have done an experiment. The voltage of a free DC power supply was set to 5V. When it was connected to a circuit, its voltage dropped to 3V. What happened? Isn't the 2V is lost in the internal resistance of the power supply. However,the power supply will...
  2. M

    Terms nodes ,loop and branches which applied to the circuits

    HI everyone I am confused by the terms nodes ,loop and branches which applied to the circuit.
  3. M

    Motor and inductor

    In these two cases , emf will be induced in different way. for motor: current +B-field-->Force-->Coil rotate-->change of magnetic flux-->emf inducedd in the coil for inductor , when the switch suddenly openfrom closes switch, there are a sudden change of magnetic flux ,there emf will be...
  4. M

    Volume of gas

    I want to ask if I have 2 cylinder container 1) 50 m3 2) 60 m3 If I inject the same no. of mole of gases into these containers respectively when I apply PV=nRT Is the volume in calculating the gases in these containers are the same??
  5. M

    Rate of reaction

    I am currently doing an experiment. The experiment is to investigate the dependence of reaction rate on conc. for the reaction between sodum thiosulphate reacts with dilute acids By varying concentrations of thiosulphate and H+ respectively in 2 experiments.We can easily find that speed of...
  6. M

    Alternating current

    In an LR circuit with alternating current , it is know that the inductance of the cable is of the order 10^-7 . With a 2 ohm resistor ,the circuit is used to measure inductance.There are 2 frequencies , 100kHZ and 1M Hz,that can be chosen for the measurement . So whyI MHz is better . I know...
  7. M

    Soft iron core

    I would like to know what is the function of soft iron core? Is there a difference in function when inserting soft iron core in inductor , motor , generator ? Thank you
  8. M

    Stationary wave

    Questions again!!!!!!! AS I know stationary can be produced by the reflection of waves in a closed tube.But how can stationary still be produced in an open tube?? Thanks for your help
  9. M

    CR and LR circuits

    Assume there is a capacitor and resistance connecting in series in a.c. Now channel 1 of the CRO acroos both the capaciotr and resistor and channel 2 across the resistor.The trace on channel 1 was taken as the p.d. across the capacitor and that on channel 2 as the current through the capacitor...
  10. M

    Hign/Low Pass filter

    I want to ask the principle behind the RC circuit and LR circuit to become Hign/Low Pass filter respectively????? How come RC circuit allow high frequencies to pass through but block the low frequencies,however vice versa in the case of LR circuit...
  11. M

    Alternating currect

    I want to ask the relationship between "IMPEDANCE" and "REACTANCE" with resistance in the simple R circuit. I don't know why we should create so many terms .They are all come from OHhm's law(ie V=IR) Is the difference is due to voltage and current is at the peak in impedance and reactance...
  12. M

    Arbitary or direction?

    -----------> direction of E-field the potential energy required to move +ions from infinity to that point is a positive value But for -ions , the potential energy required is negative Does the sign reveal the direction ,attractive force /repulsive force or any other arbitrary meaning or just...
  13. M

    The direction of flow of electrons

    I feel frustrated with the direction of flow of electrons in battery, external circuit and conductor. 1. Inside a conductor which is connected to a battery, an electric field is built up inside it. As we know electric field line starts from positive ions to negative ions. Positive ions with...
  14. M

    Question concerning Electric Field

    I want to ask things about chapter "Electric Fields" I am stucked in these words " Potential, Electric Fields, equipotential ..." 1.Why do we call potentail difference - Voltage? 2.Why do we call 2 objects have the same potentail if they are in contact with each other? 3.I am...
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