Advertisements
Advertisements
प्रश्न
A capacitor of unknown capacitance is connected across a battery of V volts. The charge stored in it is 360 μC. When potential across the capacitor is reduced by 120 V, the charge stored in it becomes 120 μC.
Calculate:
(i) The potential V and the unknown capacitance C.
(ii) What will be the charge stored in the capacitor, if the voltage applied had increased by 120 V?
Advertisements
उत्तर
(i) Initial voltage, V1 = V volts and charge stored, Q1 = 360 µC.
Q1 = CV1 …(1)
Changed potential, V2 = V − 120
Q2 = 120 µC
Q2 = CV2 ...(2)
By dividing (2) from (1), we get `Q_1/Q_2 = (CV_1)/(CV_1) ⇒360/120 = V/(V-120)⇒ V= 180` volts
`∴C = Q_1/V_1 =( 360 xx10^-6)/180 = 2 xx 10^-6 F = 2μF`
(ii) If the voltage applied had increased by 120 V, then V3 = 180 + 120 = 300 V
Hence, charge stored in the capacitor, Q3 = CV3 = 2×10-6×300 = 600 µC
संबंधित प्रश्न
A capacitor of capacitance ‘C’ is charged to ‘V’ volts by a battery. After some time the battery is disconnected and the distance between the plates is doubled. Now a slab of dielectric constant, 1 < k < 2, is introduced to fill the space between the plates. How will the following be affected? (b) The energy stored in the capacitor Justify your answer by writing the necessary expressions
The capacitance of a capacitor does not depend on
The plates of a parallel-plate capacitor are made of circular discs of radii 5⋅0 cm each. If the separation between the plates is 1⋅0 mm, what is the capacitance?
The outer cylinders of two cylindrical capacitors of capacitance 2⋅2 µF each, are kept in contact and the inner cylinders are connected through a wire. A battery of emf 10 V is connected as shown in figure . Find the total charge supplied by the battery to the inner cylinders.
Find the equivalent capacitance of the system shown in figure between the points a and b.
Consider an assembly of three conducting concentric spherical shell of radii a, b and c as shown in figure Find the capacitance of the assembly between the points Aand B.
A parallel-plate capacitor with the plate area 100 cm2 and the separation between the plates 1⋅0 cm is connected across a battery of emf 24 volts. Find the force of attraction between the plates.
Explain in detail the effect of a dielectric placed in a parallel plate capacitor.
Two spherical conductors A and B of radii a and b(b > a) are placed concentrically in the air. B is given a charge +Q and A is earthed. The equivalent capacitance of the system is ______.
