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1
JEE Main 2021 (Online) 27th July Morning Shift
+4
-1
In the given figure, a battery of emf E is connected across a conductor PQ of length 'l' and different area of cross-sections having radii r1 and r2 (r2 < r1).

Choose the correct option as one moves from P to Q :
A
Drift velocity of electron increases.
B
Electric field decreases.
C
Electron current decreases.
D
All of these
2
JEE Main 2021 (Online) 25th July Evening Shift
+4
-1
In the given potentiometer circuit arrangement, the balancing length AC is measured to be 250 cm. When the galvanometer connection is shifted from point (1) to point (2) in the given diagram, the balancing length becomes 400 cm. The ratio of the emf of two cells, $${{{\varepsilon _1}} \over {{\varepsilon _2}}}$$ is :

A
$${5 \over 3}$$
B
$${8 \over 5}$$
C
$${4 \over 3}$$
D
$${3 \over 2}$$
3
JEE Main 2021 (Online) 25th July Evening Shift
+4
-1
The given potentiometer has its wire of resistance 10$$\Omega$$. When the sliding contact is in the middle of the potentiometer wire, the potential drop across 2$$\Omega$$ resistor is :

A
10 V
B
5 V
C
$${{40} \over 9}$$ V
D
$${{40} \over 11}$$ V
4
JEE Main 2021 (Online) 25th July Morning Shift
+4
-1
In the given figure, there is a circuit of potentiometer of length AB = 10 m. The resistance per unit length is 0.1 $$\Omega$$ per cm. Across AB, a battery of emf E and internal resistance 'r' is connected. The maximum value of emf measured by this potentiometer is :

A
5 V
B
2.25 V
C
6 V
D
2.75 V
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