1
JEE Main 2019 (Online) 9th April Evening Slot
+4
-1
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 $$\Omega$$
2
JEE Main 2019 (Online) 9th April Evening Slot
+4
-1
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
3
JEE Main 2019 (Online) 9th April Evening Slot
+4
-1
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)
A
10–8 $$\Omega$$m
B
10–7 $$\Omega$$m
C
10–5 $$\Omega$$m
D
10–6 $$\Omega$$m
4
JEE Main 2019 (Online) 9th April Morning Slot
+4
-1
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
$${3 \over {4}}R$$
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