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  1. Asked: In:

    (a) In a metre bridge [Fig. 3.27], the balance point is found to be at 39.5 cm from the end A, when the resistor Y is of 12.5 Ω. Determine the resistance of X. Why are the connections between resistors in a Wheatstone or meter bridge made of thick copper strips? (b) Determine the balance point of the bridge above if X and Y are interchanged. (c) What happens if the galvanometer and cell are interchanged at the balance point of the bridge? Would the galvanometer show any current?

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    Ekani

    Get Hindi Medium and English Medium NCERT Solution for Class 12 Physics to download. Please follow the link to visit website for first and second term exams solutions. https://www.tiwariacademy.com/ncert-solutions/class-12/Physics/chapter-3/

    Get Hindi Medium and English Medium NCERT Solution for Class 12 Physics to download.
    Please follow the link to visit website for first and second term exams solutions.
    https://www.tiwariacademy.com/ncert-solutions/class-12/Physics/chapter-3/

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  2. Asked: In:

    Determine the current in each branch of the network shown in Fig. 3.30:

    Best Answer
    Ekani

    Get Hindi Medium and English Medium NCERT Solution for Class 12 Physics to download. Please follow the link to visit website for first and second term exams solutions. https://www.tiwariacademy.com/ncert-solutions/class-12/Physics/chapter-3/

    Get Hindi Medium and English Medium NCERT Solution for Class 12 Physics to download.
    Please follow the link to visit website for first and second term exams solutions.
    https://www.tiwariacademy.com/ncert-solutions/class-12/Physics/chapter-3/

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    • 1
  3. Asked: In:

    The earth’s surface has a negative surface charge density of 10⁻⁹ C m⁻². The potential difference of 400 kV between the top of the atmosphere and the surface results (due to the low conductivity of the lower atmosphere) in a current of only 1800 A over the entire globe. If there were no mechanism of sustaining atmospheric electric field, how much time (roughly) would be required to neutralise the earth’s surface? (This never happens in practice because there is a mechanism to replenish electric charges, namely the continual thunderstorms and lightning in different parts of the globe). (Radius of earth = 6.37 × 10⁶ m.)

    Best Answer
    Ekani

    Get Hindi Medium and English Medium NCERT Solution for Class 12 Physics to download. Please follow the link to visit website for first and second term exams solutions. https://www.tiwariacademy.com/ncert-solutions/class-12/Physics/chapter-3/

    Get Hindi Medium and English Medium NCERT Solution for Class 12 Physics to download.
    Please follow the link to visit website for first and second term exams solutions.
    https://www.tiwariacademy.com/ncert-solutions/class-12/Physics/chapter-3/

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  4. Asked: In:

    (a) Given n resistors each of resistance R, how will you combine them to get the (i) maximum (ii) minimum effective resistance? What is the ratio of the maximum to minimum resistance? (b) Given the resistances of 1 Ω, 2 Ω, 3 Ω, how will be combine them to get an equivalent resistance of (i) (11/3) Ω (ii) (11/5) Ω, (iii) 6 Ω, (iv) (6/11) Ω? (c) Determine the equivalent resistance of networks shown in Fig. 3.31.

    Best Answer
    Ekani

    Get Hindi Medium and English Medium NCERT Solution for Class 12 Physics to download. Please follow the link to visit website for first and second term exams solutions. https://www.tiwariacademy.com/ncert-solutions/class-12/Physics/chapter-3/

    Get Hindi Medium and English Medium NCERT Solution for Class 12 Physics to download.
    Please follow the link to visit website for first and second term exams solutions.
    https://www.tiwariacademy.com/ncert-solutions/class-12/Physics/chapter-3/

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  6. Asked: In:

    Answer the following questions: (a) Explain qualitatively on the basis of domain picture the irreversibility in the magnetisation curve of a ferromagnet. (b) The hysteresis loop of a soft iron piece has a much smaller area than that of a carbon steel piece. If the material is to go through repeated cycles of magnetisation, which piece will dissipate greater heat energy? (c) ‘A system displaying a hysteresis loop such as a ferromagnet, is a device for storing memory?’ Explain the meaning of this statement. (d) What kind of ferromagnetic material is used for coating magnetic tapes in a cassette player, or for building ‘memory stores’ in a modern computer? (e) A certain region of space is to be shielded from magnetic fields. Suggest a method.

    Best Answer
    Ekani

    Get Hindi Medium and English Medium NCERT Solution for Class 12 Physics to download. Please follow the link to visit website for first and second term exams solutions. https://www.tiwariacademy.com/ncert-solutions/class-12/Physics/chapter-5/

    Get Hindi Medium and English Medium NCERT Solution for Class 12 Physics to download.
    Please follow the link to visit website for first and second term exams solutions.
    https://www.tiwariacademy.com/ncert-solutions/class-12/Physics/chapter-5/

    See less
    • 1