1
JEE Main 2021 (Online) 25th July Evening Shift
MCQ (Single Correct Answer)
+4
-1
An electron moving with speed v and a photon moving with speed c, have same D-Broglie wavelength. The ratio of kinetic energy of electron to that of photon is :
A
$${{3c} \over v}$$
B
$${v \over {3c}}$$
C
$${v \over {2c}}$$
D
$${{2c} \over v}$$
2
JEE Main 2021 (Online) 25th July Morning Shift
MCQ (Single Correct Answer)
+4
-1
What should be the order of arrangement of de-Broglie wavelength of electron ($$\lambda$$e), an $$\alpha$$-particle ($$\lambda$$a) and proton ($$\lambda$$p) given that all have the same kinetic energy?
A
$$\lambda$$e = $$\lambda$$p = $$\lambda$$$$\alpha$$
B
$$\lambda$$e < $$\lambda$$p < $$\lambda$$$$\alpha$$
C
$$\lambda$$e > $$\lambda$$p > $$\lambda$$$$\alpha$$
D
$$\lambda$$e = $$\lambda$$p > $$\lambda$$$$\alpha$$
3
JEE Main 2021 (Online) 25th July Morning Shift
MCQ (Single Correct Answer)
+4
-1
A particle of mass 4M at rest disintegrates into two particles of mass M and 3M respectively having non zero velocities. The ratio of de-Broglie wavelength of particle of mass M to that of mass 3M will be :
A
1 : 3
B
3 : 1
C
1 : $$\sqrt 3 $$
D
1 : 1
4
JEE Main 2021 (Online) 22th July Evening Shift
MCQ (Single Correct Answer)
+4
-1
A nucleus with mass number 184 initially at rest emits an $$\alpha$$-particle. If the Q value of the reaction is 5.5 MeV, calculate the kinetic energy of the $$\alpha$$-particle.
A
5.5 MeV
B
5.0 MeV
C
5.38 MeV
D
0.12 MeV
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