MCQ
Two capacitors with capacitance values $C _1=2000 \pm 10 pF$ and $C_2=3000 \pm 15 pF$ are connected in series. The voltage applied across this combination is $V=5.00 \pm 0.02 V$. The percentage error in the calculation of the energy stored in this combination of capacitors is . . . . . .
  • $1.30$
  • B
    $1.35$
  • C
    $1.40$
  • D
    $1.45$

Answer

Correct option: A.
$1.30$
a
$U =\frac{1}{2} \frac{ C _1 C _2}{ C _1+ C _2} V ^2$

Let $C_{\text {oq }}=\frac{C_1 C_2}{ C _1+C_2}$

$\frac{1}{ C _{ eq } \pm \Delta C _{ oq }}=\frac{1}{ C _1 \pm \Delta C _1}+\frac{1}{ C _2 \pm \Delta C _2}$

$\Rightarrow C _{ eq } \pm \Delta C _{ oq } \simeq \frac{ C _1 C _2+ C _1 \Delta C _2+ C _2 \Delta C _1}{ C _1+ C _2+\Delta C _1+\Delta C _2}$

$=\frac{1200\left(1 \pm \frac{12}{1200}\right)}{\left(1 \pm \frac{25}{5000}\right)}$

$=1200\left[1 \pm\left(\frac{1}{100}-\frac{1}{200}\right)\right]$

$\frac{\Delta U }{ U } \times 100=\frac{\Delta C _{ oq }}{ C _{ eq }} \times 100+\frac{2 \Delta V }{ V } \times 100$

$=\frac{1}{200} \times 100+2 \times \frac{0.02}{5} \times 100$

$=1.3 \%$

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 coil of N turns and mean cross-sectional area A is rotating with uniform angular velocity w about an axis at right angle to uniform magnetic field B. The induced e.m.f. E in the coil will be
In an electric heater $4\, amp$ current passes for $1$ minute at potential difference of $250\, volt$, the power of heater and energy consumed will be respectively
The activity of a radioactive sample
Consider the figure (not drawn on scale) in which a converging lens of $R = 1\ cm$ and focal length $f = 20\ cm$ is cut in the middle. The Upper part is lifted up by $d = 1\ mm$ and lower part is pulled down by same distance. The gap between them is blocked by an opaque sheet. A point light source with wavelength $\lambda = 500\ nm$ is placed on the optical axis at $2f$ distance from the split lens. A large screen is placed at $L = 1\ m$ from right focus of Find the approximate number interference fringes on screen
When the energy of the incident radiation is increased by $20\%$, the kinetic energy of the photoelectrons emitted from a metal surface increased from $0.5\,\, eV$ to $0.8\, eV.$ The work function of the metal is ............. $eV$
When half of a lens is wrapped in a black cloth, what will be the effect on the image formed by the lens?
For which of the following colour, the magnifying power of a microscope will be maximum
Two charges $q_1, q_2$ exert some amount of force on each other. What will happen to the force on $q_1$ if another charge q3 is brought close to them?
$A$ rectangular coil of single turn, having area $A$, rotates in a uniform magnetic field $B$ an angular velocity $\omega$ about an axis perpendicular to the field. If initially the plane of coil is perpendicular to the field, then the average induced $e.m.f.$ when it has rotated through $90^o$ is
$X $ and $Y$ are large, parallel conducting plates closed to each other. Each face has an area $A$. $X$ is given a charge $Q$. $Y$ is without any charge. Points $A, B$ and $C$ are as shown in figure.