Current Electricity
381 Questions
2020
JEE Mains
MCQ
JEE Main 2020 (Online) 5th September Morning Slot
A galvanometer of resistance G is converted
into a voltmeter of range 0 – 1 V by connecting
a resistance R1 in series with it. The additional
resistance that should be connected in series
with R1 to increase the range of the voltmeter
to 0 – 2 V will be :
A.
G
B.
R1
C.
R1 + G
D.
R1 - G
2020
JEE Mains
MCQ
JEE Main 2020 (Online) 4th September Evening Slot
The value of current i1
flowing from A to C in the circuit diagram is :
A.
1 A
B.
4 A
C.
5 A
D.
2 A
2020
JEE Mains
MCQ
JEE Main 2020 (Online) 4th September Morning Slot
A battery of 3.0 V is connected to a resistor dissipating 0.5 W of power. If the terminal voltage of the battery is 2.5 V, the power dissipated within the internal resistance is :
A.
0.50 W
B.
0.072 W
C.
0.10 W
D.
0.125 W
2020
JEE Mains
MCQ
JEE Main 2020 (Online) 3rd September Evening Slot
Two resistors 400$\Omega $ and 800$\Omega $ are connected in series across a 6 V battery. The potential difference measured by a voltmeter of 10 k$\Omega $ across 400 $\Omega $ resistor is close to :
A.
2.05 V
B.
1.95 V
C.
2 V
D.
1.8 V
2020
JEE Mains
MCQ
JEE Main 2020 (Online) 3rd September Morning Slot
Model a torch battery of length $l$ to be made up
of a thin cylindrical bar of radius ‘a’ and a
concentric thin cylindrical shell of radius ‘b’
filled in between with an electrolyte of
resistivity $\rho $ (see figure). If the battery is
connected to a resistance of value R, the
maximum Joule heating in R will take place for :
A.
$R = {{2\rho } \over {\pi l}}\ln \left( {{b \over a}} \right)$
B.
$R = {\rho \over {\pi l}}\ln \left( {{b \over a}} \right)$
C.
$R = {\rho \over {2\pi l}}\ln \left( {{b \over a}} \right)$
D.
$R = {\rho \over {2\pi l}}\left( {{b \over a}} \right)$
2020
JEE Mains
MCQ
JEE Main 2020 (Online) 2nd September Evening Slot
A potentiometer wire PQ of 1 m length is
connected to a standard cell E1. Another cell E2
of emf 1.02 V is connected with a resistance ‘r’
and switch S (as shown in figure). With switch
S open, the null position is obtained at a
distance of 49 cm from Q. The potential
gradient in the potentiometer wire is :
A.
0.04 V/cm
B.
0.01 V/cm
C.
0.02 V/cm
D.
0.03 V/cm
2020
JEE Mains
MCQ
JEE Main 2020 (Online) 2nd September Morning Slot
Consider four conducting materials copper,
tungsten, mercury and aluminium with
resistivity $\rho $C, $\rho $T, $\rho $M and $\rho $A respectively. Then :
A.
$\rho $C > $\rho $A > $\rho $T
B.
$\rho $M > $\rho $A > $\rho $C
C.
$\rho $A > $\rho $T > $\rho $C
D.
$\rho $A > $\rho $M > $\rho $C
2020
JEE Mains
MCQ
JEE Main 2020 (Online) 9th January Morning Slot
In the given circuit diagram, a wire is joining
points B and D. The current in this wire is :
A.
4 A
B.
2 A
C.
zero
D.
0.4 A
2020
JEE Mains
MCQ
JEE Main 2020 (Online) 8th January Evening Slot
A galvanometer having a coil resistance
100 $\Omega $ gives a full scale deflection when a
current of 1 mA is passed through it. What is
the value of the resistance which can convert
this galvanometer into a voltmeter giving full
scale deflection for a potential difference of
10 V?
A.
8.9 k$\Omega $
B.
10 k$\Omega $
C.
9.9 k$\Omega $
D.
7.9 k$\Omega $
2020
JEE Mains
MCQ
JEE Main 2020 (Online) 8th January Morning Slot
The length of a potentiometer wire is 1200 cm
and it carries a current of 60 mA. For a cell of
emf 5V and internal resistance of 20$\Omega $, the null
point on it is found to be a 1000 cm. The
resistance of whole wire is :
A.
80$\Omega $
B.
60$\Omega $
C.
120$\Omega $
D.
100$\Omega $
2020
JEE Mains
MCQ
JEE Main 2020 (Online) 7th January Evening Slot
In a building there are 15 bulbs of 45 W, 15 bulbs of 100 W, 15 small fans of 10 W and 2 heaters
of 1 kW. The voltage of electric main is 220 V. The minimum fuse capacity (rated value) of the
building will be :
A.
15 A
B.
20 A
C.
25 A
D.
10 A
2020
JEE Mains
MCQ
JEE Main 2020 (Online) 7th January Morning Slot
The current I1 (in A) flowing through 1 $\Omega $ resistor in the following circuit is :
A.
0.4
B.
0.25
C.
0.2
D.
0.5
2020
JEE Mains
Numerical
JEE Main 2020 (Online) 4th September Evening Slot
Four resistances 40 $\Omega $, 60 $\Omega $, 90 $\Omega $ and 110 $\Omega $ make the arms of a quadrilateral ABCD. Across AC is
a battery of emf 40 V and internal resistance negligible.The potential difference across BD in V is
_______.
Correct Answer: 2
Explanation:
${i_1} = {{40} \over {40 + 60}} = 0.4$
${i_2} = {{40} \over {90 + 110}} = {1 \over 5}$
${V_B} + {i_1}(40) - {i_2}(90) = {V_D}$
${V_B} - {V_D} = {1 \over 5}(90) - {4 \over {10}} \times 40$
${V_B} - {V_D} = 18 - 16 = 2$
2020
JEE Mains
Numerical
JEE Main 2020 (Online) 9th January Evening Slot
In a meter bridge experiment S is a standard
resistance. R is a resistance wire. It is found
that balancing length is $l$ = 25 cm. If R is
replaced by a wire of half length and half
diameter that of R of same material, then the
balancing distance $l'$ (in cm) will now
be________.
Correct Answer: 40
Explanation:
${S \over R} = {{75} \over {25}}$ = 3
R = ${{\rho L} \over A}$ = ${{4\rho L} \over {\pi {d^2}}}$
R' = ${{4\rho \left( {{L \over 2}} \right)} \over {\pi {{\left( {{d \over 2}} \right)}^2}}}$ = 2R
Then ${S \over {R'}} = {{100 - l} \over l}$
$ \Rightarrow $ ${{100 - l} \over l}$ = ${S \over {2R}}$ = ${3 \over 2}$
$ \Rightarrow $ $l$ = 40 cm
R = ${{\rho L} \over A}$ = ${{4\rho L} \over {\pi {d^2}}}$
R' = ${{4\rho \left( {{L \over 2}} \right)} \over {\pi {{\left( {{d \over 2}} \right)}^2}}}$ = 2R
Then ${S \over {R'}} = {{100 - l} \over l}$
$ \Rightarrow $ ${{100 - l} \over l}$ = ${S \over {2R}}$ = ${3 \over 2}$
$ \Rightarrow $ $l$ = 40 cm
2020
JEE Mains
Numerical
JEE Main 2020 (Online) 8th January Evening Slot
The series combination of two batteries, both
of the same emf 10 V, but different internal
resistance of 20$\Omega $ and 5$\Omega $, is connected to the
parallel combination of two resistors 30$\Omega $ and
R $\Omega $. The voltage difference across the battery
of internal resistance 20$\Omega $ is zero, the value of
R (in $\Omega $) is : _______
Correct Answer: 30
Explanation:
10 – I × 20 = 0
$ \Rightarrow $ I = 0.5A
Also,
I = ${{10 + 10} \over {20 + 5 + {{30R} \over {30 + R}}}}$
$ \Rightarrow $ ${1 \over 2}$ = ${{20} \over {25 + {{30R} \over {30 + R}}}}$
$ \Rightarrow $ 40 = 25 + ${{{30R} \over {30 + R}}}$
$ \Rightarrow $ 15 = ${{{30R} \over {30 + R}}}$
$ \Rightarrow $ 30 + R = 2R
$ \Rightarrow $ R = 30 $\Omega $
2020
JEE Mains
Numerical
JEE Main 2020 (Online) 8th January Morning Slot
Four resistances of 15$\Omega $, 12$\Omega $, 4$\Omega $ and 10$\Omega $
respectively in cyclic order to form
Wheatstone's network. The resistance that
is to be connected in parallel with the
resistance of 10$\Omega $ to balance the network is
_____$\Omega $.
Correct Answer: 10
Explanation:
Wheatstone bridge balance condition
${{{R_1}} \over {{R_2}}} = {{{R_3}} \over {{R_4}}}$
$ \Rightarrow $ ${{15} \over 4} = {{15} \over {{{10R} \over {10 + R}}}}$
$ \Rightarrow $ 2R = 10 + R
$ \Rightarrow $ R = 10 $\Omega $
2020
JEE Mains
Numerical
JEE Main 2020 (Online) 7th January Evening Slot
The balancing length for a cell is 560 cm in a potentiometer experiment. When an external
resistance of 10 $\Omega $ is connected in parallel to the cell, the balancing length changes by 60 cm. If
the internal resistance of the ceil is ${N \over {10}}$
$\Omega $ , where N is an integer then value of N is .............
Correct Answer: 12
Explanation:
Let the emf of cell is $\varepsilon $ internal resistance is 'r' and potential gradient is x.
When only cell connected :
$\varepsilon $ = 560x .....(1)
After connecting the resistor
${{\varepsilon \times 10} \over {10 + r}}$ = 500x ....(2)
from (1) and (2)
56 = 50 +5r
r = ${6 \over 5}\Omega $ = ${N \over {10}}\Omega $
$ \Rightarrow $ N = 12
When only cell connected :
$\varepsilon $ = 560x .....(1)
After connecting the resistor
${{\varepsilon \times 10} \over {10 + r}}$ = 500x ....(2)
from (1) and (2)
56 = 50 +5r
r = ${6 \over 5}\Omega $ = ${N \over {10}}\Omega $
$ \Rightarrow $ N = 12
2019
JEE Mains
MCQ
JEE Main 2019 (Online) 12th April Evening Slot
A moving coil galvanometer, having a resistance G, produces full scale deflection when a current Ig flows
through it. This galvanometer can be converted into (i) an ammeter of range 0 to I0(I0 > Ig) by connecting a
shunt resistance RA to it and (ii) into a voltmeter of range 0 to V (V = GI0) by connecting a series resistance
RV to it. Then,
A.
${R_A}{R_V} = {G^2}$ and ${{{R_A}} \over {{R_V}}} = {{{I_g}} \over {\left( {{I_0} - {I_g}} \right)}}$
B.
${R_A}{R_V} = {G^2}\left( {{{{I_g}} \over {{I_0} - {I_g}}}} \right)$ and ${{{R_A}} \over {{R_V}}} = {\left( {{{{I_0} - {I_g}} \over {{I_g}}}} \right)^2}$
C.
${R_A}{R_V} = {G^2}\left( {{{{I_0} - {I_g}} \over {{I_g}}}} \right)$ and ${{{R_A}} \over {{R_V}}} = {\left( {{{{I_g}} \over {{I_0} - {I_g}}}} \right)^2}$
D.
${R_A}{R_V} = {G^2}$ and ${{{R_A}} \over {{R_V}}} = {\left( {{{{I_g}} \over {{I_0} - {I_g}}}} \right)^2}$
2019
JEE Mains
MCQ
JEE Main 2019 (Online) 12th April Morning Slot
To verify Ohm's law, a student connects the voltmeter across the battery as, shown in the figure. The
measured voltage is plotted as a function of the current, and the following graph is obtained :
If V0 is almost zero, identify the correct statement :
If V0 is almost zero, identify the correct statement :
A.
The value of the resistance R is 1.5 $\Omega $
B.
The emf of the battery is l.5 V and its internal resistance is 1.5 $\Omega $
C.
The emf of the battery is l.5 V and the value of R is 1.5 $\Omega $
D.
The potential difference across the battery is 1.5 V when it sends a current of 1000 mA
2019
JEE Mains
MCQ
JEE Main 2019 (Online) 12th April Morning Slot
The resistive network shown below is connected to a D.C. source of 16 V. The power consumed by the
network is 4 Watt. The value of R is:
A.
16 $\Omega $
B.
1 $\Omega $
C.
8 $\Omega $
D.
6 $\Omega $
2019
JEE Mains
MCQ
JEE Main 2019 (Online) 12th April Morning Slot
A galvanometer of resistance 100 $\Omega $ has 50 divisions on its scale and has sensitivitv of 20 $\mu $A/division. It is
to be converted to a voltmeter with three ranges of 0-2V, 0-10 V and 0-20 V. The appropriate circuit to do so
is
A.
B.
C.
D.
2019
JEE Mains
MCQ
JEE Main 2019 (Online) 10th April Evening Slot
Space between two concentric conducting spheres of radii a and b (b > a) is filled with a medium of
resistivity $\rho $. The resistance between the two spheres will be :
A.
${\rho \over {2\pi }}\left( {{1 \over a} + {1 \over b}} \right)$
B.
${\rho \over {4\pi }}\left( {{1 \over a} + {1 \over b}} \right)$
C.
${\rho \over {2\pi }}\left( {{1 \over a} - {1 \over b}} \right)$
D.
${\rho \over {4\pi }}\left( {{1 \over a} - {1 \over b}} \right)$
2019
JEE Mains
MCQ
JEE Main 2019 (Online) 10th April Morning Slot
A moving coil galvanometer allows a full scale
current of 10–4 A. A series resistance of 2 M$\Omega $
is required to convert the above galvanometer
into a voltmeter of range 0-5 V. Therefore the
value of shunt resistance required to convert the
above galvanometer into an ammeter of range
0.10 mA is :
A.
200 $\Omega $
B.
500 $\Omega $
C.
100 $\Omega $
D.
None of the options are correct
2019
JEE Mains
MCQ
JEE Main 2019 (Online) 10th April Morning Slot
In an experiment, the resistance of a material
is plotted as a function of temperature (in some
range). As shown in the figure, it is a straight
line. One may conclude that :
A.
$R(T) = {R_0}{e^{ - {T^2}/T_0^2}}$
B.
$R(T) = {{{R_0}} \over {{T^2}}}$
C.
$R(T) = {R_0}{e^{ {T^2}/T_0^2}}$
D.
$R(T) = {R_0}{e^{ - T_0^2/{T^2}}}$
2019
JEE Mains
MCQ
JEE Main 2019 (Online) 10th April Morning Slot
A current of 5 A passes through a copper
conductor (resistivity = 1.7 × 10–8 $\Omega $m) of radius
of cross-section 5 mm. Find the mobility of the
charges if their drift velocity is 1.1 × 10–3 m/s.
A.
1.3 m2/Vs
B.
1.0 m2/Vs
C.
1.8 m2/Vs
D.
1.5 m2/Vs
2019
JEE Mains
MCQ
JEE Main 2019 (Online) 10th April Morning Slot
In the given circuit, an ideal voltmeter
connected across the 10$\Omega $ resistance reads 2V.
The internal resistance r, of each cell is:
A.
1.5 $\Omega $
B.
1 $\Omega $
C.
0.5 $\Omega $
D.
0 $\Omega $
Given that VAB = 2 V
2019
JEE Mains
MCQ
JEE Main 2019 (Online) 10th April Morning Slot
In a meter bridge experiment, the circuit
diagram and the corresponding observation
table are shown in figure
Which of the readings is inconsistent?
| SI. No. | R($\Omega $) | l(cm) |
|---|---|---|
| 1. | 1000 | 60 |
| 2. | 100 | 13 |
| 3. | 10 | 1.5 |
| 4. | 1 | 1.0 |
A.
4
B.
3
C.
2
D.
1
2019
JEE Mains
MCQ
JEE Main 2019 (Online) 9th April Evening Slot
The resistance of a galvanometer is 50 ohm and
the maximum current which can be passed
through it is 0.002 A. What resistance must be
connected to it in order to convert it into an
ammeter of range 0 – 0.5 A ?
A.
0.02 ohm
B.
0.2 ohm
C.
0.002 ohm
D.
0.5 ohm
2019
JEE Mains
MCQ
JEE Main 2019 (Online) 9th April Evening Slot
A metal wire of resistance 3 $\Omega $ is elongated to
make a uniform wire of double its previous
length. This new wire is now bent and the ends
joined to make a circle. If two points on this
circle make an angle 60° at the centre, the
equivalent resistance between these two points
will be :-
A.
5 /2 $\Omega $
B.
12/5 $\Omega $
C.
7/2 $\Omega $
D.
5 / 3 $\Omega $
2019
JEE Mains
MCQ
JEE Main 2019 (Online) 9th April Evening Slot
In a conductor, if the number of conduction
electrons per unit volume is 8.5 × 1028 m–3 and
mean free time is 25ƒs (femto second), it's
approximate resistivity is :-
(me = 9.1 × 10–31 kg)
(me = 9.1 × 10–31 kg)
A.
10–8 $\Omega $m
B.
10–7 $\Omega $m
C.
10–5 $\Omega $m
D.
10–6 $\Omega $m
2019
JEE Mains
MCQ
JEE Main 2019 (Online) 9th April Morning Slot
A wire of resistance R is bent to form a square
ABCD as shown in the figure. The effective
resistance between E and C is :
(E is mid-point of arm CD)
A.
${7 \over {64}}R$
B.
${1 \over {16}}R$
C.
R
D.
${3 \over {4}}R$
2019
JEE Mains
MCQ
JEE Main 2019 (Online) 9th April Morning Slot
A moving coil galvanometer has resistance 50$\Omega $
and it indicates full deflection at 4mA current.
A voltmeter is made using this galvanometer
and a 5 k$\Omega $ resistance. The maximum voltage,
that can be measured using this voltmeter, will
be close to :
A.
15 V
B.
10 V
C.
40 V
D.
20 V
2019
JEE Mains
MCQ
JEE Main 2019 (Online) 8th April Evening Slot
In the figure shown, what is the current
(in Ampere) drawn from the battery ?
You are given: R1 = 15$\Omega $, R2 = 10 $\Omega $, R3 = 20 $\Omega $, R4 = 5$\Omega $, R5 = 25$\Omega $, R6 = 30 $\Omega $, E = 15 V
You are given: R1 = 15$\Omega $, R2 = 10 $\Omega $, R3 = 20 $\Omega $, R4 = 5$\Omega $, R5 = 25$\Omega $, R6 = 30 $\Omega $, E = 15 V
A.
13/24
B.
7/18
C.
9/32
D.
20/3
2019
JEE Mains
MCQ
JEE Main 2019 (Online) 8th April Evening Slot
In the circuit shown, a four-wire potentiometer
is made of a 400 cm long wire, which extends
between A and B. The resistance per unit length
of the potentiometer wire is r = 0.01 $\Omega $/cm. If
an ideal voltmeter is connected as shown with
jockey J at 50 cm from end A, the expected
reading of the voltmeter will be :-
A.
0.25 V
B.
0.20 V
C.
0.50V
D.
0.75 V
2019
JEE Mains
MCQ
JEE Main 2019 (Online) 8th April Evening Slot
A cell of internal resistance r drives current
through an external resistance R. The power
delivered by the cell to the external resistance
will be maximum when :-
A.
R = 1000 r
B.
R = r
C.
R = 2r
D.
R = 0.001 r
2019
JEE Mains
MCQ
JEE Main 2019 (Online) 8th April Morning Slot
For the circuit shown, with R1 = 1.0W, R2 = 2.0 W,
E1 = 2 V and E2 = E3 = 4 V, the potential
difference between the points 'a' and 'b' is
approximately (in V):
A.
3.3
B.
2.7
C.
2.3
D.
3.7
2019
JEE Mains
MCQ
JEE Main 2019 (Online) 8th April Morning Slot
A 200 $\Omega $ resistor has a certain color code. If one
replaces the red color by green in the code, the
new resistance will be :
A.
500 $\Omega $
B.
100 $\Omega $
C.
200 $\Omega $
D.
300 $\Omega $
2019
JEE Mains
MCQ
JEE Main 2019 (Online) 12th January Evening Slot
In the given circuit diagram, the currents, I1 = – 0.3 A, I4 = 0.8 A and I5 = 0.4 A, are flowing as shown. The currents I2, I3 and I6, respectively, are :
A.
1.1 A, – 0.4 A, 0.4 A
B.
$-$ 0.4 A, 0.4 A, 1.1 A
C.
0.4 A, 1.1 A, 0.4 A
D.
1.1 A, 0.4 A, 0.4 A
2019
JEE Mains
MCQ
JEE Main 2019 (Online) 12th January Evening Slot
A galvanometer, whose resistance is 50 ohm, has 25 divisions in it. When a current of 4 $ \times $ 10–4 A passes through it, its needle ( pointer) deflects by one division. To use this galvanometer as a voltmeter of range 2.5 V, it should be connected to a resistance of :
A.
200 ohm
B.
250 ohm
C.
6200 ohm
D.
6250 ohm
2019
JEE Mains
MCQ
JEE Main 2019 (Online) 12th January Morning Slot
Two electric bulbs, rated at (25 W, 220 V) and (100 W, 220 V), are connected in series across a 220 V voltage source. If the 25 W and 100 W bulbs draw powers P1 and P2 respectively, then :
A.
P1 = 4W, P2 = 16 W
B.
P1 = 16W, P2 = 4 W
C.
P1 = 9W, P2 = 16 W
D.
P1 = 16W, P2 = 9 W
2019
JEE Mains
MCQ
JEE Main 2019 (Online) 12th January Morning Slot
In a meter bridge, the wire of length 1 m has a non-uniform cross-section such that, the variation ${{dR} \over {d\ell }}$ of its resistance R with length $\ell $ is ${{dR} \over {d\ell }}$ $ \propto $ ${1 \over {\sqrt \ell }}$. Two equal resistances are connected as shown in the figure. The
galvanometer has zero deflection when the jockey is at point P. What is the length AP ?
A.
0.3 m
B.
0.25 m
C.
0.35 m
D.
0.2 m
2019
JEE Mains
MCQ
JEE Main 2019 (Online) 12th January Morning Slot
The galvanometer deflection, when key K1 is closed but K2 is open, equals $\theta $0 (see figure). On closing K2 also and adjusting R2 to 5$\Omega $, the deflection in galvanometer becomes ${{{\theta _0}} \over 5}.$ . The resistance of the galvanometer is, then, given by [Neglect the internal resistance of battery] :
A.
5 $\Omega $
B.
25 $\Omega $
C.
12 $\Omega $
D.
22 $\Omega $
2019
JEE Mains
MCQ
JEE Main 2019 (Online) 12th January Morning Slot
An ideal battery of 4 V and resistance R are connected in series in the primary circuit of a potentiometer of length 1 m and esistance 5 $\Omega $. The value of R, to give a potential difference of 5 mV across 10 cm of potentiometer wire, is :
A.
480 $\Omega $
B.
495 $\Omega $
C.
490 $\Omega $
D.
395 $\Omega $
2019
JEE Mains
MCQ
JEE Main 2019 (Online) 11th January Evening Slot
A galvanometer having a resistance of 20 $\Omega $ and 30 divisions on both sides has figure of merit 0.005 ampere/division. The resistance that should be connected in series such that it can be used as a voltmeter upto 15 volt, is:
A.
120 $\Omega $
B.
125 $\Omega $
C.
80 $\Omega $
D.
100 $\Omega $
2019
JEE Mains
MCQ
JEE Main 2019 (Online) 11th January Evening Slot
In the experimental set up of metre bridge shown in the figure, the null point is obtained at a distance of 40 cm from A. If a 10 $\Omega $ resistor is connected in series with R1, the null point shifts by 10 cm. The resistance that should be connected in parallel with (R1 + 10) $\Omega $ such that the null point shifts back to its initial position is :
A.
40 $\Omega $
B.
30 $\Omega $
C.
20 $\Omega $
D.
60 $\Omega $
2019
JEE Mains
MCQ
JEE Main 2019 (Online) 11th January Evening Slot
In the circuit shown, the potential difference between A and B is :
A.
6 V
B.
3 V
C.
2 V
D.
1 V
2019
JEE Mains
MCQ
JEE Main 2019 (Online) 11th January Morning Slot
Two equal resistances when connected in series to a battery, consume electric power of 60 W. If these resistances are now connected in parallel combination to the same battery, the electric power consumed will be :
A.
240 W
B.
60 W
C.
30 W
D.
120 W
2019
JEE Mains
MCQ
JEE Main 2019 (Online) 11th January Morning Slot
The resistance of the meter bridge AB in given figure is 4 $\Omega $. With a cell of emf $\varepsilon $ = 0.5 V and rheostat
resistance Rh = 2 $\Omega $ the null point is obtained at some point J. When the cell is replaced by another one of emf $\varepsilon $ = $\varepsilon $2 the same null point J is found for Rh = 6 $\Omega $. The emf $\varepsilon $2 is, :
A.
0.3 V
B.
0.6 V
C.
0.5 V
D.
0.4 V
2019
JEE Mains
MCQ
JEE Main 2019 (Online) 11th January Morning Slot
In a Wheatstone bridge(see fig.), Resistances P and Q are approximately equal. When R = 400 $\Omega $, the bridge
is balanced. On interchanging P and Q, the value of R, for balance, is 405 $\Omega $. The value of X is close to :
A.
402.5 ohm
B.
401.5 ohm
C.
403.5 ohm
D.
404.5 ohm
2019
JEE Mains
MCQ
JEE Main 2019 (Online) 10th January Evening Slot
A current of 2 mA was passed through an unknown resistor which dissipated a power of 4.4 W. Dissipated power when an ideal power supply of 11 V is connected across it is -
A.
11 $ \times $ 10–5 W
B.
11 $ \times $ 10–3 W
C.
11 $ \times $ 105 W
D.
11 $ \times $ 10–4 W