MCQs of Atoms

Atoms MCQs

Showing 81 to 90 out of 146 Questions

81.

The wavelength of the first line of Lyman series is λ. The wavelength of the first line in Balmer series is _____.

(a)	$\frac{27}{5} λ$
(b)	$\frac{5}{27} λ$
(c)	$\frac{9}{2} λ$
(d)	$\frac{2}{5} λ$

82.

The difference of wave number of lines with maximum and minimum wavelength in Balmer series of hydrogen atom is _____ m^-1.(R = 1.097 × 10⁷m^-1)

(a)	1.219× 10⁶
(b)	1.219× 10^-6
(c)	1219
(d)	1.219× 10⁷

83.

In hydrogen atom, an electron makes transition from n = 3 to n = 1 state in time interval of 1.2× 10^-8 s, calculate average torque (in Nm) acting on the electron during this transition _____.

(a)	1.055× 10^-26
(b)	4.40× 10^-27
(c)	1.7× 10^-26
(d)	8.79× 10^-27

84.

The ionization potentials of hydrogenic ions A and B are V_A and V_B, respectively. Now if V_B > V_A,then _____

(a)	r_A> r_B
(b)	r_A< r_B
(c)	r_A= r_B
(d)	None of the above

85.

The operating voltage in a Coolidge tube is 10⁵ V. The speed of X-rays produced is _____ ms^-1.

(a)	2 × 10⁸
(b)	2 × 10⁸
(c)	10⁵
(d)	10⁶

86.

The wavelength of K_α spectral line is λ for an element of atomic number 43. The wavelength of K_α spectral line for an element of atomic number 29 is _____λ.

(a)	$\frac{43}{29}$
(b)	$\frac{42}{28}$
(c)	$\frac{9}{4}$
(d)	$\frac{4}{9}$

87.

If f₁, f₂ and f₃ are the frequencies corresponding to K_α, K_β and L_α X-rays for the given target. Then _____ .

(a)	f₁= f₂= f₃
(b)	f₁- f₂= f₃
(c)	f₂= f₁+ f₃
(d)	f₃- f₂= f₁

88.

A particle of energy 5 MeV is scattered through 180° by a stationary uranium nucleus. The distance of closest approach is the order of _____ .

(a)	1 Å
(b)	10^-10 cm
(c)	10^-12 cm
(d)	10^-15 cm

89.

The radius of first orbit of hydrogen atom 0.53 Å, The radius of its fourth orbit will be _____.

(a)	0.913 Å
(b)	4.24 Å
(c)	2.12 Å
(d)	8.48 Å

90.

The velocity of an electron in the ground state H - atom is nearly _____ .

(a)	2 × 10⁷ m/s
(b)	2 × 10⁶ m/s
(c)	2 × 10⁷ m/s
(d)	2 × 10⁶ m/s

Showing 81 to 90 out of 146 Questions