MCQ
Two identical capacitors are connected in parallel across a potenial difference $V$. After they are fully charged, the positive plate of first capacitor is connected to negative plate of second and negative plate of first is connected to positive plate of other. The loss of energy will be
  • A
    $\frac{1}{2} C V^2$
  • $CV ^2$
  • C
    $\frac{1}{4} C V^2$
  • D
    $0$

Answer

Correct option: B.
$CV ^2$
b
(b)

$U_i=\frac{1}{2} C V^2+\frac{1}{2} C V^2=C V^2$

$U_f=0$

$\Delta U=C V^2$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Similar questions

A photon of wavelength $\lambda $ is scattered from an electron, which was at rest. The wavelength shift $\Delta \lambda $ is three times of $ \lambda $ and the angle of scattering $\theta $ is $60^o$ . The angle at which the electron recoiled is $\phi $. The value of $tan\,\phi $ is : ( electron speed is much smaller than the speed of light)
The critical angle between an equilateral prism and air is 45°. If the incident ray is perpendicular to the refracting surface, then
A source of sound moves towards an observer.
The energy density in the electric field created by a point charge falls off with the distance from the point charge as:
A bar magnet has coercivity $4 \times 10^3 \mathrm{Am}^{-1}$. It is desired to demagnetise it by inserting it inside a solenoid 12 cm long and having 60 turns. The current that should be sent through the solenoid is
In the given circuit, rms value of current $\left( I _{ rms }\right)$ through the resistor $R$ is :$..........\,A$
Glass has refractive index m with respect to air and the critical angle for a ray of light going from glass to air is q. If a ray of light is incident from air on the glass with angle of incidence q, the corresponding angle of refraction is
Two thin wire rings each having a radius R are placed at a distance d apart with their axes coinciding. The charges on the two rings are +q and -q. The potential difference between the centres of the two rings is
The electrostatic potential on the perpendicular bisector due to an electric dipole is $......$
The frequency of $K_{\alpha} , K_{\beta}$ and $L_{\alpha}$ $X-$ rays of a material are $\gamma _1, \gamma _2$ and $\gamma _3 $ respectively. Which of the following relations holds good ?