1
JEE Main 2019 (Online) 8th April Morning Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
An upright object is placed at a distance of 40 cm in front of a convergent lens of focal length 20 cm. A convergent mirror of focal length 10 cm is placed at a distance of 60 cm on the other side of the lens. The position and size of the final image will be :
A
20 cm from the convergent mirror, same size as the object
B
40 cm from the convergent mirror, same size as the object
C
40 cm from the convergent lens, same size as the object
D
20 cm from the convergent mirror, twice the size of the object
2
JEE Main 2019 (Online) 8th April Morning Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
Two particles move at right angle to each other. Their de-Broglie wavelengths are $$\lambda _1$$ and $$\lambda _2$$ respectively. The particles suffer perfectly inelastic collision. The de-Broglie wavelength $$\lambda _2$$ of the final particle, is given by :
A
$$\lambda = {{{\lambda _1} + {\lambda _2}} \over 2}$$
B
$${1 \over {{\lambda ^2}}} = {1 \over {\lambda _1^2}} + {1 \over {\lambda _2^2}}$$
C
$$\lambda = \sqrt {{\lambda _1}{\lambda _2}} $$
D
$${2 \over \lambda } = {1 \over {{\lambda _1}}} + {1 \over {{\lambda _2}}}$$
3
JEE Main 2019 (Online) 8th April Morning Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
A thermally insulated vessel contains 150g of water at 0°C. Then the air from the vessel is pumped out adiabatically. A fraction of water turns into ice and the rest evaporates at 0°C itself. The mass of evaporated water will be closest to : (Latent heat of vaporization of water = 2.10 × 106 J kg–1 and Latent heat of Fusion of water = 3.36 × 105 J kg–1)
A
35 g
B
130 g
C
20 g
D
150 g
4
JEE Main 2019 (Online) 8th April Morning Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
A thin circular plate of mass M and radius R has its density varying as $$\rho $$(r) = $$\rho $$0r with $$\rho $$0 as constant and r is the distance from its centre. The moment of Inertia of the circular plate about an axis perpendicular to the plate and passing through its edge is I = aMR2. The value of the coefficient a is :
A
$${1 \over 2}$$
B
$${3 \over 2}$$
C
$${8 \over 5}$$
D
$${3 \over 5}$$

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