MCQ
A physical quantity $Q$ is found to depend on quantities $a, b, c$ by the relation $Q=\frac{a^4 b^3}{c^2}$. The percentage error in $a$, $b$ and $c$ are $3 \%, 4 \%$ and $5 \%$ respectively. Then, the percentage error in $\mathrm{Q}$ is :
  • A
     $66 \%$
  • B
     $43 \%$
  •  $34 \%$
  • D
     $14 \%$

Answer

Correct option: C.
 $34 \%$
c
$ \mathrm{Q}=\frac{\mathrm{a}^4 \mathrm{~b}^3}{\mathrm{c}^2} $

$ \frac{\Delta \mathrm{Q}}{\mathrm{Q}}=4 \frac{\Delta \mathrm{a}}{\mathrm{a}}+3 \frac{\Delta \mathrm{b}}{\mathrm{b}}+2 \frac{\Delta \mathrm{c}}{\mathrm{c}} $

$ \frac{\Delta \mathrm{Q}}{\mathrm{Q}} \times 100=4\left(\frac{\Delta \mathrm{a}}{\mathrm{a}} \times 100\right)+3\left(\frac{\Delta \mathrm{b}}{\mathrm{b}} \times 100\right)+2\left(\frac{\Delta \mathrm{c}}{\mathrm{c}} \times 100\right) $

$ \% \text { error in } \mathrm{Q}=4 \times 3 \%+3 \times 4 \%+2 \times 5 \% $

$=12 \%+12 \%+10 \% $

$=34 \%$

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

Two bodies at different temperatures are mixed in a calorimeter. Which of the following quantities remains conserved?
Two capillary of length $L $ and $2L$  and of radius $R$  and $2R$  are connected in series. The net rate of flow of fluid through them will be (given rate of the flow through single capillary, $X = \pi P{R^4}/8\eta L)$
A string tied on a roof can bear a maximum tension of $50 \,kg$ wt. The minimum acceleration that can be acquired by a man of $98 \,kg$ to descend will be ...... $m / s ^2$ [Take $g=9.8 \,m / s ^2$ ]
If density of earth increased $4 $ times and its radius become half of what it is, our weight will
A $bob$ of mass $m$ attached to an inextensible string of length $l$ is suspended from a vertical support. The $bob$ rotates in a horizontal circle with an angular speed $\omega\,  rad/s$ about the vertical. About the point of suspension
A tuning fork $A$ of frequency $200 Hz$ is sounded with fork $B,$ the number of beats per second is $5.$ By putting some wax on $A,$ the number of beats increases to $8.$ The frequency of fork $B$ is  .... $Hz$
Some liquid is filled in a cylindrical vessel of radius $R$. Let $ F_1 $ be the force applied by the liquid on the bottom of the cylinder. Now the same liquid is poured into a vessel of uniform square crss-section of side $R$. Let $F_2$ be the force applied by the liquid on the bottom of this new vessel. Then:
The value of R in SI unit will be:
The $SI$ unit of the inductance, the henry cannot be written as
A source supplies heat to a system at the rate of $1000 \,W$. If the system performs work at a rate of $200\,W$. The rate at which internal energy of the system increases $.......\,W$