1
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
$$\sqrt {{{8\pi } \over 3}} $$
2
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
3
JEE Main 2021 (Online) 18th March Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
A solid cylinder of mass m is wrapped with an inextensible light string and, is placed on a rough inclined plane as shown in the figure. The frictional force acting between the cylinder and the inclined plane is :

JEE Main 2021 (Online) 18th March Evening Shift Physics - Rotational Motion Question 89 English
[The coefficient of static friction, $$\mu$$s' is 0.4]
A
0
B
5 mg
C
$${7 \over 2}$$ mg
D
$${{mg} \over 5}$$
4
JEE Main 2021 (Online) 18th March Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
The function of time representing a simple harmonic motion with a period of $${\pi \over \omega }$$ is :
A
cos($$\omega$$t) + cos(2$$\omega$$t) + cos(3$$\omega$$t)
B
sin2($$\omega$$t)
C
sin($$\omega$$t) + cos($$\omega$$t)
D
3cos$$\left( {{\pi \over 4} - 2\omega t} \right)$$
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