1
JEE Main 2019 (Online) 12th January Morning Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
A person standing on an open ground hears the sound of a jet aeroplane, coming from north at an angle 60o with ground level. But he finds the aeroplane right vertically above his position. If v is the speed of sound, speed of the plane is :
A
$${{\sqrt 3 } \over 2}$$v
B
$${{2v} \over {\sqrt 3 }}$$
C
v
D
$${v \over 2}$$
2
JEE Main 2019 (Online) 12th January Morning Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
The output of the given logic circuit is :

JEE Main 2019 (Online) 12th January Morning Slot Physics - Semiconductor Question 188 English
A
$$\overline A B$$
B
$$AB + \overline {AB} $$
C
$$A\overline B + \overline A B$$
D
$$A\overline B $$
3
JEE Main 2019 (Online) 12th January Morning Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
As shown in the figure, two infinitely long, identical wires are bent by 90o and placed in such a way that the segments LP and QM are along the x-axis, while segments PS and QN are parallel to the y-axis. If OP = OQ = 4cm, and the magnitude of the magnetic field at O is 10–4 T, and the two wires carry equal currents (see figure), the magnitude of the current in each wire and the direction of the magnetic field at O will be ($$\mu $$0 = 4$$\pi $$ $$ \times $$ 10–7 NA–2) :

JEE Main 2019 (Online) 12th January Morning Slot Physics - Magnetic Effect of Current Question 188 English
A
40 A, perpendicular into the page
B
40 A, perpendicular out of the page
C
20 A, perpendicular into the page
D
40 A, perpendicular out of the page
4
JEE Main 2019 (Online) 12th January Morning Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
In the figure shown, after the switch 'S' is turned from position 'A' to position 'B', the energy dissipated in the circuit in terms of capacitance 'C' and total charge 'Q' is :

JEE Main 2019 (Online) 12th January Morning Slot Physics - Capacitor Question 138 English
A
$${1 \over 8}{{{Q^2}} \over C}$$
B
$${5 \over 8}{{{Q^2}} \over C}$$
C
$${3 \over 4}{{{Q^2}} \over C}$$
D
$${3 \over 8}{{{Q^2}} \over C}$$

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