1
JEE Main 2019 (Online) 11th January Morning Slot
+4
-1
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
2
JEE Main 2019 (Online) 11th January Morning Slot
+4
-1
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
3
JEE Main 2019 (Online) 10th January Evening Slot
+4
-1
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
4
JEE Main 2019 (Online) 10th January Evening Slot
+4
-1
The Wheatstone bridge shown in figure, here, gets balanced when the carbon resistor used as R1 has the colour code (Orange, Red, Brown). The resistors R2 and R4 are 80$$\Omega$$ and 40$$\Omega$$, respectively. Assuming that the colour code for the carbon resistors gives their accurate values, the colour code for the carbon resistor, used as R3, would be -

A
Brown, Blue, Brown
B
Grey, Black, Brown
C
Red, Green, Brown
D
Brown, Blue, Black
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