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
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
3
JEE Main 2020 (Online) 3rd September Evening Slot
+4
-1
Two sources of light emit X-rays of wavelength 1 nm and visible light of wavelength 500 nm, respectively. Both the sources emit light of the same power 200 W. The ratio of the number density of photons of X-rays to the number density of photons of the visible light of the given wavelengths is :
A
$${1 \over {500}}$$
B
500
C
250
D
$${1 \over {250}}$$
4
JEE Main 2020 (Online) 3rd September Morning Slot
+4
-1
When the wavelength of radiation falling on a metal is changed from 500 nm to 200 nm, the maximum kinetic energy of the photoelectrons becomes three times larger. The work function of the metal is close to :
A
1.02 eV
B
0.81 eV
C
0.61 eV
D
0.52 eV
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