# The energy required to ionize doubly ionized Li (Z = 3) is:

1. 13.6 eV
2. 27.4 eV
3. 54.4 eV
4. 108.8 eV
5. 122.4 eV

1. 10-6 seconds
2. 10-8 seconds
3. 10-10 seconds
4. 10-12 seconds

# The energy which is released when an atom is formed from its constituent particles?

1. Atomic energy
2. Binding energy
3. Nuclear energy
4. Thermal energy

# When a hydrogen atom is raised from the ground state to an excited state:

1. Both K.E and P.E increase
2. Both K.E and P.E decrease
3. P.E increases, K.E decreases
4. K.E increases, P.E decreases

# In 1911, Rutherford concluded that the central part of the atom called the nucleus is:

1. Positively charged
2. Negatively charged
3. Both positively and negatively charged
4. Electrically neutral

# In hydrogen atom on decreasing the principal quantum number n the value of radius (r) and frequency (f) will:

1. decrease
2. increase
3. radius increase and frequency decrease
4. frequency increase and radius decrease

1. 2n + l
2. 2n + 2l
3. 2(2l + 1)
4. 2l + 1

# If a nucleus with Z = 80 emits the particles in the following sequence:

1. α, β, β, α, α, α, α, α, β, β, β+, α, β+
2. What is the value of Z of the resulting nucleus
1. 56
2. 66
3. 78
4. 82

# The radius of the first orbit of the electron in the hydrogen atom is 0.53 A0. Then the radius of the second orbit is:

1. 2.12 A0
2. 4.24 A0
3. 0.193 A0
4. None of the above

1. hf/c
2. hc/f
3. hc/λ
4. λ/hc

# Nuclear forces are stronger than:

1. Gravitational forces
2. Electrostatics forces
3. Magnetic forces
4. All of the above forces