1
JEE Main 2017 (Offline)
+4
-1
The radius of the second Bohr orbit for hydrogen atom is:
(Planck’s Const. h = 6.6262 × 10-34 Js; mass of electron = 9.1091 × 10-31 kg; charge of electron (e) = 1.60210 × 10-19 C; permittivity of vacuum ($${\varepsilon _0}$$) = 8.854185 × 10-12 kg-1 m-3 A2)
A
4.76 $$\mathop {\rm A}\limits^o$$
B
2.12 $$\mathop {\rm A}\limits^o$$
C
0.529 $$\mathop {\rm A}\limits^o$$
D
1.65 $$\mathop {\rm A}\limits^o$$
2
JEE Main 2017 (Offline)
+4
-1
The group having isoelectronic species is:
A
O2- , F- , Na+, Mg2+
B
O2- , F- , Na, Mg2+
C
O- , F- , Na+, Mg2+
D
O- , F- , Na, Mg+
3
JEE Main 2016 (Online) 9th April Morning Slot
+4
-1
The total number of orbitals associated with the principal quantum number 5 is :
A
5
B
10
C
20
D
25
4
JEE Main 2016 (Offline)
+4
-1
A stream of electrons from a heated filament was passed between two charged plates kept at a potential difference V esu. If e and m are charge and mass of an electron, respectively, then the value of h / $$\lambda$$ (where $$\lambda$$ is wavelength associated with electron wave) is given by :
A
2meV
B
$$\sqrt {meV}$$
C
$$\sqrt {2meV}$$
D
meV
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