1
JEE Main 2022 (Online) 25th June Evening Shift
+4
-1

Two cells of same emf but different internal resistances r1 and r2 are connected in series with a resistance R. The value of resistance R, for which the potential difference across second cell is zero, is :

A
r2 $$-$$ r1
B
r1 $$-$$ r2
C
r1
D
r2
2
JEE Main 2022 (Online) 25th June Evening Shift
+4
-1

If n represents the actual number of deflections in a converted galvanometer of resistance G and shunt resistance S. Then the total current I when its figure of merit is K will be:

A
$${{KS} \over {(S + G)}}$$
B
$${{(G + S)} \over {nKS}}$$
C
$${{nKS} \over {(G + S)}}$$
D
$${{nK(G + S)} \over S}$$
3
JEE Main 2022 (Online) 25th June Morning Shift
+4
-1

In the figure, a very large plane sheet of positive charge is shown. P1 and P2 are two points at distance l and 2l from the charge distribution. If $$\sigma$$ is the surface charge density, then the magnitude of electric fields E1 and E2 at P1 and P2 respectively are :

A
$${E_1} = \sigma /{\varepsilon _0},\,{E_2} = \sigma /2{\varepsilon _0}$$
B
$${E_1} = 2\sigma /{\varepsilon _0},\,{E_2} = \sigma /{\varepsilon _0}$$
C
$${E_1} = {E_2} = \sigma /2{\varepsilon _0}$$
D
$${E_1} = {E_2} = \sigma /{\varepsilon _0}$$
4
JEE Main 2022 (Online) 25th June Morning Shift
+4
-1

A teacher in his physics laboratory allotted an experiment to determine the resistance (G) of a galvanometer. Students took the observations for $${1 \over 3}$$ deflection in the galvanometer. Which of the below is true for measuring value of G?

A
$${1 \over 3}$$ deflection method cannot be used for determining the resistance of the galvanometer.
B
$${1 \over 3}$$ deflection method can be used and in this case the G equals to twice the value of shunt resistances.
C
$${1 \over 3}$$ deflection method can be used and in this case, the G equals to three times the value of shunt resistances.
D
$${1 \over 3}$$ deflection method can be used and in this case the G value equals to the shunt resistances.
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Modern Physics
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