1
JEE Main 2019 (Online) 12th January Morning Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
An ideal gas occupies a volume of 2m3 at a pressure of 3 $$ \times $$ 106 Pa. The energy of the gas is :
A
6 $$ \times $$ 104 J
B
9$$ \times $$ 106 J
C
3 $$ \times $$ 102 J
D
108 J
2
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
$${v \over 2}$$
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 147 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
A particle of mass m moves in a circular orbit in a central potential field U(r) = $${1 \over 2}$$ kr2. If Bohr 's quantization conditions are applied, radii of possible orbitls and energy levels vary with quantum number n as :
A
rn $$ \propto $$ $$\sqrt n $$, En $$ \propto $$ n
B
rn $$ \propto $$ $$\sqrt n $$, En $$ \propto $$ $${1 \over n}$$
C
rn $$ \propto $$ n, En $$ \propto $$ n
D
rn $$ \propto $$ n2, En $$ \propto $$ $${1 \over {{n^2}}}$$
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