1
JEE Main 2021 (Online) 17th March Morning Shift
MCQ (Single Correct Answer)
+4
-1
An electron of mass m and a photon have same energy E. The ratio of wavelength of electron to that of photon is : (c being the velocity of light)
A
$${1 \over c}{\left( {{{2m} \over E}} \right)^{1/2}}$$
B
$${1 \over c}{\left( {{E \over {2m}}} \right)^{1/2}}$$
C
$${\left( {{E \over {2m}}} \right)^{1/2}}$$
D
$$c{(2mE)^{1/2}}$$
2
JEE Main 2021 (Online) 16th March Evening Shift
MCQ (Single Correct Answer)
+4
-1
The de-Broglie wavelength associated with an electron and a proton were calculated by accelerating them through same potential of 100 V. What should nearly be the ratio of their wavelengths? (mp = 1.00727u me = 0.00055u)
A
41.4 : 1
B
(1860)2 : 1
C
1860 : 1
D
43 : 1
3
JEE Main 2021 (Online) 16th March Morning Shift
MCQ (Single Correct Answer)
+4
-1
The stopping potential in the context of photoelectric effect depends on the following property of incident electromagnetic radiation :
A
Phase
B
Frequency
C
Amnplitude
D
Intensity
4
JEE Main 2021 (Online) 26th February Evening Shift
MCQ (Single Correct Answer)
+4
-1
The recoil speed of a hydrogen atom after it emits a photon in going from n = 5 state to n = 1 state will be :
A
4.34 m/s
B
2.19 m/s
C
3.25 m/s
D
4.17 m/s
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