1
JEE Main 2020 (Online) 7th January Evening Slot
+4
-1
An emf of 20 V is applied at time t = 0 to a circuit containing in series 10 mH inductor and 5 $$\Omega$$ resistor. The ratio of the currents at time t = $$\infty$$ and at t = 40 s is close to : (Take e2 = 7.389)
A
1.06
B
0.84
C
1.15
D
1.46
2
JEE Main 2020 (Online) 7th January Morning Slot
+4
-1
A LCR circuit behaves like a damped harmonic oscillator. Comparing it with a physical spring-mass damped oscillator having damping constant 'b', the correct equivalence would be:
A
L $$\leftrightarrow$$ k, C $$\leftrightarrow$$ b, R $$\leftrightarrow$$ m
B
L $$\leftrightarrow$$ m, C $$\leftrightarrow$$ k, R $$\leftrightarrow$$ b
C
L $$\leftrightarrow$$ m, C $$\leftrightarrow$$ $${1 \over k}$$, R $$\leftrightarrow$$ b
D
L $$\leftrightarrow$$ $${1 \over b}$$, C $$\leftrightarrow$$ $${1 \over m}$$, R $$\leftrightarrow$$ $${1 \over k}$$
3
JEE Main 2019 (Online) 12th April Evening Slot
+4
-1
Consider the LR circuit shown in the figure. If the switch S is closed at t = 0 then the amount of charge that passes through the battery between t = 0 and t = $${L \over R}$$ is :
A
$${{2.7EL} \over {{R^2}}}$$
B
$${{EL} \over {2.7{R^2}}}$$
C
$${{7.3EL} \over {{R^2}}}$$
D
$${{EL} \over {7.3{R^2}}}$$
4
JEE Main 2019 (Online) 10th April Evening Slot
+4
-1
A coil of self inductance 10 mH and resistance 0.1 $$\Omega$$ is connected through a switch to a battery of internal resistance 0.9 $$\Omega$$. After the switch is closed, the time taken for the current to attain 80% of the saturation value is: [take ln 5 = 1.6]
A
0.324 s
B
0.002 s
C
0.103 s
D
0.016 s
EXAM MAP
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