1. Ans (a). Dielectric constant of the mica sheet, k= 6 If voltage supply remained connected, voltage between two plates will be constant. Supply voltage, V = 100 V Initial capacitance, C= 1.771 x 10-11 F New capacitance, C₁ = kC = 6 x 1.771 x 10-11 F = 106 pF New charge, q₁ = C₁V = 106 x 100 pC = 1.06Read more

    Ans (a).
    Dielectric constant of the mica sheet, k= 6

    If voltage supply remained connected, voltage between two plates will be constant.

    Supply voltage, V = 100 V

    Initial capacitance, C= 1.771 x 10-11 F

    New capacitance, C₁ = kC = 6 x 1.771 x 10-11 F = 106 pF

    New charge, q₁ = C₁V = 106 x 100 pC = 1.06 x 108 C

    Potential across the plates remains 100 V.

    Ans (b).

    Dielectric constant, k= 6

    Initial capacitance, C = 1.771 x 10-11 F

    New capacitance, C₁= kC = 6 x 1.771 x 10-11 F = 106 pF

    If supply voltage is removed, then there will be constant amount of charge in the plates.

    Charge = 1.771 x 109 C

    Potential across the plates is given by,

    V₁q/C₁= (1.771 x 109)/(106 x 10⁻¹²)

    =16.7 V

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  2. Area of each plate of the parallel plate capacitor, A = 6 x 10-3 m2 Distance between the plates, d = 3 mm = 3 x 10-3 m Supply voltage, V = 100 V Capacitance C of a parallel plate capacitor is given by, C = ε0 A/d Where, ε0  = Permittivity of free space = 8.854 x 10-12 N-1m-2 C-2 Therefore C =  (8.85Read more

    Area of each plate of the parallel plate capacitor, A = 6 x 10-3 m2

    Distance between the plates, d = 3 mm = 3 x 103 m

    Supply voltage, V = 100 V

    Capacitance C of a parallel plate capacitor is given by, C = εA/d

    Where,

    ε = Permittivity of free space = 8.854 x 10-12 N-1m-2 C-2

    Therefore C =  (8.854 x 10-12 x 6 x 103)/3 x 103

    = 17.71 x 10-12 F = 17.71 pF

    So, charge on each plate of the capacitor

    q = VC = 100 x 17.71 x 10-12  C = 1.771 x 109 C
    Therefore, capacitance of the capacitor is 17.71 pF and charge on each plate is 1.771 x 109 C.

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  3. Ans (a). Capacitances of the given capacitors: C₁ = 2 pF, C2 = 3 pF and C3 = 4 pF For the parallel combination of the capacitors, equivalent capacitor is given by Ceq the algebraic sum, Therefore Ceq = C₁+C2 + C3 = 2 + 3+ 4 = 9pF Therefore, total capacitance of the combination is 9 pF. Ans (b). SuppRead more

    Ans (a).
    Capacitances of the given capacitors: C₁ = 2 pF, C2 = 3 pF and C3 = 4 pF

    For the parallel combination of the capacitors, equivalent capacitor is given by Ceq the algebraic sum,

    Therefore Ceq = C₁+C2 + C3 = 2 + 3+ 4 = 9pF

    Therefore, total capacitance of the combination is 9 pF.

    Ans (b).
    Supply voltage, V = 100 V

    The voltage through all the three capacitors is same = V = 100 V

    Charge on a capacitor of capacitance C and potential difference V is given by the relation,

    q=VC… (i)

    For C = 2 pF, charge = VC = 100 x 2 = 200 pC  = 2   x lO⁻10 C

    For C = 3 pF, charge = VC = 100 x 3 = 300 pC   = 3   x lO⁻10 C

    For C = 4 pF, charge = VC = 100 x 4 = 400 pC  = 4   x 10⁻10 C

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  4. (a) Capacitance of each of the three capacitors, C = 9 pF Equivalent capacitance (Ceq) of the combination of the capacitors is given by the relation, 1/Ceq =1/C + 1/C + 1/C = 3/C = 3/9 = 1/3 => 1/Ceq = 1/3 =>  Ceq = 3 pF Therefore, total capacitance of the combination is 3 pF. (b) Supply voltaRead more

    (a) Capacitance of each of the three capacitors, C = 9 pF

    Equivalent capacitance (Ceq) of the combination of the capacitors is given by the relation,

    1/Ceq =1/C + 1/C + 1/C = 3/C = 3/9 = 1/3

    => 1/Ceq = 1/3 =>  Ceq = 3 pF

    Therefore, total capacitance of the combination is 3 pF.

    (b) Supply voltage, V = 100 V

    Potential difference (V₁) across each capacitor is equal to one-third of the supply voltage.

    Therefore V1=V/3=120/3=40V

    Therefore, the potential difference across each capacitor is 40 V.

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  5. Capacitance between the parallel plates of the capacitor, C = 8 pF Initially, distance between the parallel plates was d and it was filled with air. Dielectric constant of air, k = 1 Capacitance, C, is given by the formula, C = (kε0 A)/d = ε0 A/d -----------------------Eq-1 Where, A = Area of each pRead more

    Capacitance between the parallel plates of the capacitor, C = 8 pF

    Initially, distance between the parallel plates was d and it was filled with air.

    Dielectric constant of air, k = 1

    Capacitance, C, is given by the formula,

    C = (kε0 A)/d = ε0 A/d ———————–Eq-1

    Where,

    A = Area of each plate

    ε0 = Permittivity of free space

    If distance between the plates is reduced to half, then new distance, di = d/2 Dielectric constant of the substance filled in between the plates, k₁= 6 Hence, capacitance of the capacitor becomes

    C₁ = k₁ ε0 A/d₁ = (6 ε0 A)/(d/2) = (12 εA)/d………………Eq-2

    Taking ratios of equations (1) and (2), we obtain C₁ = 2 x 6 C = 12 C = 12 x 8 pF = 96 pF Therefore, the capacitance between the plates is 96 pF.

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