1. In a balanced Wheatstone bridge, the central galvanometer branch can be ignored. The two parallel arms each have resistance 2R, and their equivalent resistance is: Req = 2R×2R/2R +2R = R Answer: (a) R For more visit here: https://www.tiwariacademy.com/ncert-solutions/class-12/physics/chapter-3/

    In a balanced Wheatstone bridge, the central galvanometer branch can be ignored.

    The two parallel arms each have resistance 2R, and their equivalent resistance is:

    Req = 2R×2R/2R +2R = R
    Answer: (a) R

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  2. Using the meter bridge formula: R/S = L/100 - L Given R = 2Ω and L = 40 cm: 2/S = 40/60 S = 2 × 60/40 = 3Ω Answer: (b) 0.5 Ω For more visit here: https://www.tiwariacademy.com/ncert-solutions/class-12/physics/chapter-3/

    Using the meter bridge formula:

    R/S = L/100 – L
    Given R = 2Ω and

    L = 40 cm:
    2/S = 40/60
    S = 2 × 60/40 = 3Ω
    Answer: (b) 0.5 Ω

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  3. Drift velocity vd is given by = vd = eEτ/m, Where E = V/L. Thus, vd = eVr/mL Since vd is directly proportional to V, the correct answer is (c) V. For more visit here: https://www.tiwariacademy.com/ncert-solutions/class-12/physics/chapter-3/

    Drift velocity vd is given by = vd = eEτ/m, Where E = V/L. Thus,
    vd = eVr/mL
    Since vd is directly proportional to V, the correct answer is (c) V.

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  4. Current is given by I = Q/t ​For A: I = 300/60 = 5A (correct). For B: Charge Q = (3.125 10) (1.6 10) = 5C, so I = 5A (correct). Thus, both A and B are correct. Answer: (c) both A and B. For more visit here: https://www.tiwariacademy.com/ncert-solutions/class-12/physics/chapter-3/

    Current is given by I = Q/t
    ​For A: I = 300/60 = 5A (correct).
    For B: Charge Q = (3.125 10) (1.6 10) = 5C, so I = 5A (correct).
    Thus, both A and B are correct. Answer: (c) both A and B.

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  5. The resistance of the bulb is R =220²/100= 484Ω . When operated at 110V, power consumed is P ′ = 110²/484 = 25W. thus, the Correct answer: (a) 25 W. For more visit here: https://www.tiwariacademy.com/ncert-solutions/class-12/physics/chapter-3/

    The resistance of the bulb is

    R =220²/100= 484Ω
    . When operated at 110V, power consumed is

    P ′ = 110²/484 = 25W.
    thus, the Correct answer: (a) 25 W.

    For more visit here:
    https://www.tiwariacademy.com/ncert-solutions/class-12/physics/chapter-3/

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