Figure shows a simple potentiometer circuit for measuring a small… - Vidyadip

MCQ

Figure shows a simple potentiometer circuit for measuring a small $e.m.f$. produced by a thermocouple. The meter wire $PQ$ has a resistance $5 \,\Omega$ and the driver cell has an e.m.f. of $2\, V$. If a balance point is obtained $0.600\, m$ along $PQ$ when measuring an e.m.f. of $6.00\, mV$, what is the value of resistance $R$ ............... $\Omega$

✓
$995 $
B
$1995$
C
$2995$
D
None of these

✓

Answer

Correct option: A.

$995 $

a
(a) The voltage per unit light of the metre wire $PQ$ is $\left( {\frac{{6.00\,mV}}{{0.600\,m}}} \right)$ i.e. $10\,mV/m$.

Hence potential difference across the metre wire is $10\,mV{\rm{/}}m \times 1\,m = 10\,mV$.

The current drawn from the driver cell is $i = \frac{{10\,mV}}{{5\,\Omega }} = 2\,mA$.

The resistance $R = \frac{{(2\,V - 10\,mV)}}{{2\,mA}} = \frac{{1990\,mV}}{{2\,mA}} = 995\;\Omega $.

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

Explore more

JEE STD 11 Science question papers→Gujarat Board STD 11 Science question papers→Gujarat Board question paper generator→

Similar questions

The binding energy of the innermost electron in tungsten is $40 keV$. To produce characteristic $X-$ rays using a tungsten target in an $X-$ rays tube the potential difference $V$ between the cathode and the anti-cathode should be

A square loop of edge length $2 \mathrm{~m}$ carrying current of $2 \mathrm{~A}$ is placed with its edges parallel to the $\mathrm{x}-\mathrm{y}$ axis. A magnetic field is passing through the $x-y$ plane and expressed as $\vec{B}=B_0(1+4 x) \hat{k}$, where $\mathrm{B}_0=5 \mathrm{~T}$. The net magnetic force experienced by the loop is. . . . . . . $\mathrm{N}$.

A boy walks to his school at a distance of $6\, km$ with constant speed of $2.5\, km/hour $ and walks back with a constant speed of $4 \,km/hr.$ His average speed for round trip expressed in $km/hour$, is

Light waves producing interference have their amplitudes in the ratio $3 : 2$. The intensity ratio of maximum and minimum of interference fringes is

A deviation of $2^{\circ}$ is produced in the yellow ray when prism of crown and flint glass are achromatically combined. Taking dispersive powers of crown and flint glass are $0.02$ and $0.03$ respectively and refractive index for yellow light for these glasses are $1.5$ and $1.6$ respectively. The refracting angles for crown glass prism will be $........\,^{\circ}$ (in degree) (Round off to the Nearest Integer)

A source of sound $S$ of frequency $500 Hz$ situated between a stationary observer $O$ and a wall $W$, moves towards the wall with a speed of $2 m/s$. If the velocity of sound is $332 m/s$, then the number of beats per second heard by the observer is (approximately)

A body is executing simple harmonic motion of amplitude $a$ and period $T$ about the equilibrium position $x=0$. Large numbers of snapshots are taken at random of this body in motion. The probability of the body being found in a very small interval $x$ to $x+|d x|$ is highest at

Find the speed of the intersection point $O$ of the two wires if the wires starts moving perpendicular to itself with speed $v$ as shown in figure.

A galvanometer coil has a resistance of $12\,\Omega $ and meter shows full scale deftection for a current of $3\,mA$ then to convert it into a voltmeter of range $0\,-18\, V$ a resistance should be added

The root mean square velocity of molecules of gas is