1
JEE Main 2021 (Online) 27th August Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
Two discs have moments of inertia I1 and I2 about their respective axes perpendicular to the plane and passing through the centre. They are rotating with angular speeds, $$\omega$$1 and $$\omega$$2 respectively and are brought into contact face to face with their axes of rotation coaxial. The loss in kinetic energy of the system in the process is given by :
A
$${{{I_1}{I_2}} \over {({I_1} + {I_2})}}{({\omega _1} - {\omega _2})^2}$$
B
$${{{{({I_1} - {I_2})}^2}{\omega _1}{\omega _2}} \over {2({I_1} + {I_2})}}$$
C
$${{{I_1}{I_2}} \over {2({I_1} + {I_2})}}{({\omega _1} - {\omega _2})^2}$$
D
$${{{{({\omega _1} - {\omega _2})}^2}} \over {2({I_1} + {I_2})}}$$
2
JEE Main 2021 (Online) 27th August Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
Three capacitors C1 = 2$$\mu$$F, C2 = 6$$\mu$$F and C3 = 12$$\mu$$F are connected as shown in figure. Find the ratio of the charges on capacitors C1, C2 and C3 respectively :

JEE Main 2021 (Online) 27th August Evening Shift Physics - Capacitor Question 78 English
A
2 : 1 : 1
B
2 : 3 : 3
C
1 : 2 : 2
D
3 : 4 : 4
3
JEE Main 2021 (Online) 27th August Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
if the rms speed of oxygen molecules at 0$$^\circ$$C is 160 m/s, find the rms speed of hydrogen molecules at 0$$^\circ$$C.
A
640 m/s
B
40 m/s
C
80 m/s
D
332 m/s
4
JEE Main 2021 (Online) 27th August Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
A constant magnetic field of 1T is applied in the x > 0 region. A metallic circular ring of radius 1m is moving with a constant velocity of 1 m/s along the x-axis. At t = 0s, the centre of O of the ring is at x = $$-$$1m. What will be the value of the induced emf in the ring at t = 1s? (Assume the velocity of the ring does not change.)

JEE Main 2021 (Online) 27th August Evening Shift Physics - Electromagnetic Induction Question 67 English
A
1V
B
2$$\pi$$V
C
2V
D
0V
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