1
JEE Main 2021 (Online) 18th March Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
Consider a uniform wire of mass M and length L. It is bent into a semicircle. Its moment of inertia about a line perpendicular to the plane of the wire passing through the center is :
A
$${1 \over 4}{{M{L^2}} \over {{\pi ^2}}}$$
B
$${1 \over 2}{{M{L^2}} \over {{\pi ^2}}}$$
C
$${2 \over 5}{{M{L^2}} \over {{\pi ^2}}}$$
D
$${{M{L^2}} \over {{\pi ^2}}}$$
2
JEE Main 2021 (Online) 18th March Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
The velocity $$-$$ displacement graph of a particle is shown in the figure.

JEE Main 2021 (Online) 18th March Evening Shift Physics - Motion in a Straight Line Question 70 English
The acceleration $$-$$ displacement graph of the same particle is represented by :
A
JEE Main 2021 (Online) 18th March Evening Shift Physics - Motion in a Straight Line Question 70 English Option 1
B
JEE Main 2021 (Online) 18th March Evening Shift Physics - Motion in a Straight Line Question 70 English Option 2
C
JEE Main 2021 (Online) 18th March Evening Shift Physics - Motion in a Straight Line Question 70 English Option 3
D
JEE Main 2021 (Online) 18th March Evening Shift Physics - Motion in a Straight Line Question 70 English Option 4
3
JEE Main 2021 (Online) 18th March Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
Consider a sample of oxygen behaving like an ideal gas. At 300 K, the ratio of root mean square (rms) velocity to the average velocity of gas molecule would be :

(Molecular weight of oxygen is 32g/mol; R = 8.3 J K$$-$$1 mol$$-$$1)
A
$$\sqrt {{{3\pi } \over 8}} $$
B
$$\sqrt {{3 \over 3}} $$
C
$$\sqrt {{8 \over 3}} $$
D
$$\sqrt {{{8\pi } \over 3}} $$
4
JEE Main 2021 (Online) 18th March Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
The time taken for the magnetic energy to reach 25% of its maximum value, when a solenoid of resistance R, inductance L is connected to a battery, is :
A
infinite
B
$${L \over R}$$ ln10
C
$${L \over R}$$ ln2
D
$${L \over R}$$ ln5
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