1
JEE Main 2018 (Online) 15th April Evening Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
The de-Broglie's wavelength of electron present in first Bohr orbit of 'H' atom is :
A
0.529 $$\mathop {\rm A}\limits^ \circ $$
B
2$$\pi $$ $$ \times $$ 0.529 $$\mathop {\rm A}\limits^ \circ $$
C
$${{0.529} \over {2\pi }}$$ $$\mathop {\rm A}\limits^ \circ $$
D
4 $$ \times $$ 0.529 $$\mathop {\rm A}\limits^ \circ $$
2
JEE Main 2018 (Online) 15th April Morning Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
Ejection of the photoelectron from metal in the photoelectric experiment can be stopped by applying 0.5 V when the radiation of 250 nm is used. The work function of the metal is :
A
4 eV
B
4.5 eV
C
5 eV
D
5.5 eV
3
JEE Main 2017 (Online) 9th April Morning Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
The electron in the hydrogen atom undergoes transition from higher orbitals to orbital of radius 211.6 pm. This transition is associated with :
A
Lyman series
B
Balmer series
C
Paschen series
D
Brackett series
4
JEE Main 2017 (Online) 8th April Morning Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
If the shortest wavelength in Lyman series of hydrogen atom is A, then the longestwavelength in Paschen series of He+ is :
A
$${{5A} \over 9}$$
B
$${{9A} \over 5}$$
C
$${{36A} \over 5}$$
D
$${{36A} \over 7}$$
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