1
JEE Main 2021 (Online) 20th July Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
The entropy of any system is given by
$$S = {\alpha ^2}\beta \ln \left[ {{{\mu kR} \over {J{\beta ^2}}} + 3} \right]$$ where $$\alpha$$ and $$\beta$$ are the constants. $$\mu$$, J, k and R are no. of moles, mechanical equivalent of heat, Boltzmann constant and gas constant respectively.
[Take $$S = {{dQ} \over T}$$]
Choose the incorrect option from the following :
A
$$\alpha$$ and J have the same dimensions.
B
S and $$\alpha$$ have different dimensions
C
S, $$\beta$$, k and $$\mu$$R have the same dimensions
D
$$\alpha$$ and k have the same dimensions
2
JEE Main 2021 (Online) 20th July Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
AC voltage V(t) = 20 sin$$\omega$$t of frequency 50 Hz is applied to a parallel plate capacitor. The separation between the plates is 2 mm and the area is 1 m2. The amplitude of the oscillating displacement current for the applied AC voltage is _________. [Take $$\varepsilon $$0 = 8.85 $$\times$$ 10$$-$$12 F/m]
A
55.58 $$\mu$$A
B
21.14 $$\mu$$A
C
27.79 $$\mu$$A
D
83.37 $$\mu$$A
3
JEE Main 2021 (Online) 20th July Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
Region I and II are separated by a spherical surface of radius 25 cm. An object is kept in region I at a distance of 40 cm from the surface. The distance of the image from the surface is :

JEE Main 2021 (Online) 20th July Morning Shift Physics - Geometrical Optics Question 101 English
A
55.44 cm
B
18.23 cm
C
9.52 cm
D
37.58 cm
4
JEE Main 2021 (Online) 20th July Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
A person whose mass is 100 kg travels from Earth to Mars in a spaceship. Neglect all other objects in sky and take acceleration due to gravity on the surface of the Earth and Mars as 10 m/s2 and 4 m/s2 respectively. Identify from the below figures, the curve that fits best for the weight of the passenger as a function of time.

JEE Main 2021 (Online) 20th July Morning Shift Physics - Gravitation Question 105 English
A
(b)
B
(c)
C
(d)
D
(a)
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