Q.1. Which series comes in visible region of hydrogen spectrum ?
(A) Lyman series
(B) Blamer series
(C) Paschen series
(D) Brackett series
Ans:- (B)
Q.2. The minimum angular momentum of electron in hydrogen atom will be
(A) h/π Js
(B) nh/2π Js
(C) hπ Js
(D) 2πh Js
Ans:- (B)
Q.3. The number of photons of frequency 10¹⁴ Hz in radiation of 6.62 joule will be
(A) 10¹⁰
(B) 10¹⁵
(C) 10²⁰
(D) 10²⁵
Ans:- (C)
Q.4. Who had studied the visible region of hydrogen spectrum for the first time ?
(A) Balmer
(B) Lyman
(C) Brackett
(D) Pfund
Ans:- (A)
Q.5. The SI unit of Rydberg constant
(A) m⁻¹
(B) m
(C) s⁻¹
(D) s
Ans:- (A)
Q.6. The electrons in Bohr atom move in circular orbit due to
(A) nuclear force
(B) gravitational force
(C) coulomb force
(D) none of these
Ans:- (C)
Q.7. Thomson method determines
(A) momentum of electron
(B) charge of electron
(C) mass of electron
(D) the ratio of charge to mass
Ans:- (D)
Q.8. Dimensional formula of Rydberg’s constant is
(A) [M⁰L⁻¹T⁰]
(B) [MLT⁻¹]
(C) [M⁰LT⁰]
(D) [M⁰L⁰T⁰]
Ans:- (A)
Q.9. Which of the following atoms has the lowest ionization potential ?
(A) ₇N¹⁴
(B) ₅₅Cs¹³³
(C) ₁₈Ar⁴⁰
(D) ₈O¹⁶
Ans:- (B)
Q.10.