1
JEE Main 2021 (Online) 18th March Morning Shift
MCQ (Single Correct Answer)
+4
-1
In the experiment of Ohm's law, a potential difference of 5.0 V is applied across the end of a conductor of length 10.0 cm and diameter of 5.00 mm. The measured current in the conductor is 2.00 A. The maximum permissible percentage error in the resistivity of the conductor is :
A
3.9
B
8.4
C
7.5
D
3.0
2
JEE Main 2021 (Online) 17th March Evening Shift
MCQ (Single Correct Answer)
+4
-1
Two cells of emf 2E and E with internal resistance r1 and r2 respectively are connected in series to an external resistor R (see figure). The value of R, at which the potential difference across the terminals of the first cell becomes zero is

JEE Main 2021 (Online) 17th March Evening Shift Physics - Current Electricity Question 113 English
A
r1 $$-$$ r2
B
$${{{r_1}} \over 2} - {r_2}$$
C
$${{{r_1}} \over 2} + {r_2}$$
D
r1 + r2
3
JEE Main 2021 (Online) 17th March Evening Shift
MCQ (Single Correct Answer)
+4
-1
The four arms of a Wheatstone bridge have resistances as shown in the figure. A galvanometer of 15$$\Omega$$ resistance is connected across BD. Calculate the current through the galvanometer when a potential difference of 10V is maintained across AC.

JEE Main 2021 (Online) 17th March Evening Shift Physics - Current Electricity Question 114 English
A
4.87 $$\mu$$A
B
4.87 mA
C
2.44 mA
D
2.44 $$\mu$$A
4
JEE Main 2021 (Online) 17th March Morning Shift
MCQ (Single Correct Answer)
+4
-1
A current of 10A exists in a wire of cross-sectional area of 5 mm2 with a drift velocity of 2 $$\times$$ 10$$-$$3 ms$$-$$1. The number of free electrons in each cubic meter of the wire is ___________.
A
625 $$\times$$ 1025
B
1 $$\times$$ 1023
C
2 $$\times$$ 1025
D
2 $$\times$$ 106
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