Science (English Medium) Class 12 - CBSE Question Bank Solutions

Figure shows two parallel plate capacitors with fixed plates and connected to two batteries. The separation between the plates is the same for the two capacitors. The plates are rectangular in shape with width b and lengths l₁ and l₂. The left half of the dielectric slab has a dielectric constant K₁ and the right half K₂. Neglecting any friction, find the ration of the emf of the left battery to that of the right battery for which the dielectric slab may remain in equilibrium.

Consider the situation shown in figure. The plates of the capacitor have plate area A and are clamped in the laboratory. The dielectric slab is released from rest with a length a inside the capacitor. Neglecting any effect of friction or gravity, show that the slab will execute periodic motion and find its time period.

The figure show a network of five capacitors connected to a 10V battery. Calculate the charge acquired by the 5μF capacitor.

State Gauss’s law for magnetism. Explain its significance. 

Answer the following question.
State Gauss's law for magnetism. Explain its significance.

Three circuits, each consisting of a switch 'S' and two capacitors, are initially charged, as shown in the figure. After the switch has been closed, in which circuit will the charge on the left-hand capacitor
(i) increase,
(ii) decrease, and
(iii) remains the same? Give reasons.

State Gauss's law in electrostatics. Show, with the help of a suitable example along with the figure, that the outward flux due to a point charge 'q'. in vacuum within a closed surface, is independent of its size or shape and is given by `q/ε_0`

State Gauss’s law on electrostatics and drive expression for the electric field due to a long straight thin uniformly charged wire (linear charge density λ) at a point lying at a distance r from the wire.

The variation of inductive reactance (X_L) of an inductor with the frequency (f) of the ac source of 100 V and variable frequency is shown in fig.

1. Calculate the self-inductance of the inductor.
2. When this inductor is used in series with a capacitor of unknown value and a resistor of 10 Ω at 300 s^–1, maximum power dissipation occurs in the circuit. Calculate the capacitance of the capacitor.

Obtain the expression for capacitance for a parallel plate capacitor.

The Gaussian surface ______.

A capacitor is charged by a battery. The battery is removed and another identical uncharged capacitor is connected in parallel. The total electrostatic energy of resulting system ______.

The positive terminal of 12 V battery is connected to the ground. Then the negative terminal will be at ______.

1. Charge on each capacitor remains same and equals to the main charge supplied by the battery.
2. Potential difference and energy distribute in the reverse ratio of capacitance.
3. Effective capacitance is even les than the least of teh individual capacitances.