1
JEE Main 2019 (Online) 12th January Morning Slot
+4
-1
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 $$\Omega$$
2
JEE Main 2019 (Online) 12th January Morning Slot
+4
-1
Out of Syllabus
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 $$\Omega$$
3
JEE Main 2019 (Online) 12th January Morning Slot
+4
-1
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
4
JEE Main 2019 (Online) 12th January Morning Slot
+4
-1
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
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