1
JEE Main 2020 (Online) 4th September Morning Slot
+4
-1
Particle A of mass mA = $${m \over 2}$$ moving along the x-axis with velocity v0 collides elastically with another particle B at rest having mass mB = $${m \over 3}$$. If both particles move along the x-axis after the collision, the change $$\Delta$$$$\lambda$$ in de-Broglie wavlength of particle A, in terms of its de-Broglie wavelength ($$\lambda$$0) before collision is :
A
$$\Delta$$$$\lambda$$ = $${5 \over 2}{\lambda _0}$$
B
$$\Delta$$$$\lambda$$ = $${3 \over 2}{\lambda _0}$$
C
$$\Delta$$$$\lambda$$ = 2$$\lambda$$0
D
$$\Delta$$$$\lambda$$ = 4$$\lambda$$0
2
JEE Main 2020 (Online) 4th September Morning Slot
+4
-1
A Tennis ball is released from a height h and after freely falling on a wooden floor it rebounds and reaches height $${h \over 2}$$. The velocity versus height of the ball during its motion may be represented graphically by :
(graph are drawn schematically and on not to scale)
A
B
C
D
3
JEE Main 2020 (Online) 4th September Morning Slot
+4
-1
A air bubble of radius 1 cm in water has an upward acceleration 9.8 cm s–2. The density of water is 1 gm cm–3 and water offers negligible drag force on the bubble. The mass of the bubble is (g = 980 cm/s2).
A
1.52 gm
B
4.51 gm
C
3.15 gm
D
4.15 gm
4
JEE Main 2020 (Online) 4th September Morning Slot
+4
-1
Given figure shows few data points in a phot electric effect experiment for a certain metal. The minimum energy for ejection of electron from its surface is:
(Plancks constant h = 6.62 × 10–34 J.s)
A
2.10 eV
B
2.27 eV
C
2.59 eV
D
1.93 eV
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Joint Entrance Examination