1
JEE Main 2020 (Online) 3rd September Evening Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
Two resistors 400$$\Omega $$ and 800$$\Omega $$ are connected in series across a 6 V battery. The potential difference measured by a voltmeter of 10 k$$\Omega $$ across 400 $$\Omega $$ resistor is close to :
A
2.05 V
B
1.95 V
C
2 V
D
1.8 V
2
JEE Main 2020 (Online) 3rd September Morning Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
Model a torch battery of length $$l$$ to be made up of a thin cylindrical bar of radius ‘a’ and a concentric thin cylindrical shell of radius ‘b’ filled in between with an electrolyte of resistivity $$\rho $$ (see figure). If the battery is connected to a resistance of value R, the maximum Joule heating in R will take place for : JEE Main 2020 (Online) 3rd September Morning Slot Physics - Current Electricity Question 207 English
A
$$R = {{2\rho } \over {\pi l}}\ln \left( {{b \over a}} \right)$$
B
$$R = {\rho \over {\pi l}}\ln \left( {{b \over a}} \right)$$
C
$$R = {\rho \over {2\pi l}}\ln \left( {{b \over a}} \right)$$
D
$$R = {\rho \over {2\pi l}}\left( {{b \over a}} \right)$$
3
JEE Main 2020 (Online) 2nd September Evening Slot
MCQ (Single Correct Answer)
+4
-1
Out of Syllabus
Change Language
A potentiometer wire PQ of 1 m length is connected to a standard cell E1. Another cell E2 of emf 1.02 V is connected with a resistance ‘r’ and switch S (as shown in figure). With switch S open, the null position is obtained at a distance of 49 cm from Q. The potential gradient in the potentiometer wire is : JEE Main 2020 (Online) 2nd September Evening Slot Physics - Current Electricity Question 208 English
A
0.04 V/cm
B
0.01 V/cm
C
0.02 V/cm
D
0.03 V/cm
4
JEE Main 2020 (Online) 2nd September Morning Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
Consider four conducting materials copper, tungsten, mercury and aluminium with resistivity $$\rho $$C, $$\rho $$T, $$\rho $$M and $$\rho $$A respectively. Then :
A
$$\rho $$C > $$\rho $$A > $$\rho $$T
B
$$\rho $$M > $$\rho $$A > $$\rho $$C
C
$$\rho $$A > $$\rho $$T > $$\rho $$C
D
$$\rho $$A > $$\rho $$M > $$\rho $$C
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