1
JEE Main 2017 (Online) 8th April Morning Slot
+4
-1
A potentiometer PQ is set up to compare two resistances as shown in the figure. The ammeter A in the circuit reads 1.0 A when two way key K3 is open. The balance point is at a length $$\ell$$1 cm from P when two way key K3 is plugged in between 2 and 1, while the balance point is at a length $$\ell$$2 cm from P when key K3 is plugged in between 3 and 1. The ratio of two resistances $${{{R_1}} \over {{R_2}}}$$, is found to be :

A
$${{{l_1}} \over {{l_1} + {l_2}}}$$
B
$${{{l_2}} \over {{l_2} - {l_1}}}$$
C
$${{{l_1}} \over {{l_1} - {l_2}}}$$
D
$${{{l_1}} \over {{l_2} - {l_1}}}$$
2
JEE Main 2017 (Online) 8th April Morning Slot
+4
-1

A 9 V battery with internal resistance of 0.5 $$\Omega$$ is connected across an infinite network as shown in the figure. All ammeters A1, A2, 3 and voltmeter V are ideal.
Choose correct statement.
A
Reading of A1 is 2 A
B
Reading of A1 is 18 A
C
Reading of   V   is  9 V
D
Reading of   V   is   7 V
3
JEE Main 2017 (Offline)
+4
-1
In the given circuit diagram when the current reaches steady state in the circuit, the charge on the capacitor of capacitance C will be:

A
$$CE{{{r_1}} \over {({r_1} + r)}}$$
B
CE
C
$$CE{{{r_1}} \over {({r_2} + r)}}$$
D
$$CE{{{r_2}} \over {(r + {r_2})}}$$
4
JEE Main 2017 (Offline)
+4
-1
Which of the following statements is false?
A
Kirchhoff’s second law represents energy conservation.
B
Wheatstone bridge is the most sensitive when all the four resistances are of the same order of magnitude.
C
In a balanced wheatstone bridge if the cell and the galvanometer are exchanged, the null point is disturbed.
D
A rheostat can be used as a potential divider.
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