MATRIC • FSC • NTS • ETEA • CSS • PMS etc MCQs Learn, Practice, Prepare, Succeed! Prepare Today, Succeed Tomorrow!

Q: Hydrogen atom in its ground state observed energy from the incident photon. which makes a transitions to energy level characterized by n=4 the number of lines observed are: (ET 2009)

A) 8

B) 4

C) 6

D) 10

Q: Which series of hydrogen spectrum lies in the ultraviolet region? (ET 2009)

A) Lyman

B) Balmer

C) Paschen

D) Pfund

Q: Region of spectrum used to determine structure of crystalline solids (ET 2011)

A) Visible

B) Infrared

C) X-rays

D) Ultraviolet

Q: If an atom exists in excited state n=5, maximum number of transitions takes place is (ET 2011)

A) 6

B) 5

C) 10

D) 3

Q: The ground state energy of H-atom is 13.6 eV . The energy needed to ionize H-atom from its second excited state is: (ET 2016)

A) 1.51 eV

B) 3.4 eV

C) 13.6 eV

D) 21.1 eV

Q: Electron drops from n≥3 to n=2. The spectral lines fall in which region? (ET 2015)

A) Visible

B) Ultraviolet

C) Infrared

D) None

Q: A laser beam can be sharply focused because it is (ET 2015)

A) Highly coherent

B) Intense

C) Plane polarized

D) Highly directional

Q: The shortest wavelength of radiation in Paschen series is (ET 2012)

A) RH/9

B) 9/RH

C) 9RH

D) 9+RH

Q: Lyman series lies in which part of the spectrum? (ET 2012)

A) Visible

B) Infrared

C) Ultraviolet

D) X-rays

Q: If an electron moves from n=1 to n=2, by how much does the radius increase? (Entry Test 2012)

A) 2 times

B) 3 times

C) 4 times

D) 5 times

Q: Rutherford's scattering experiment demonstrates (ET 2014)

A) Existence of X-rays

B) Existence of alpha particles

C) Mass-to-charge ratio of electron

D) Nuclear model of atom

Q: Which hydrogen spectral series lies in the visible region? (ET 2014)

A) Lyman

B) Paschen

C) Balmer

D) Pfund

Q: The half-life of radioactive source is 2.3 days. Its decay constant per day will be (Entry Test 2006)

A) 0.1

B) 0.2

C) 0.3

D) 2.3

Q: A neutron with K.E equal to 0.04 eV is called (ET 2016)

A) Slow neutron

B) Thermal neutron

C) Fast neutron

D) Both (a) and (b)

Q: Fast neutrons can be slowed down by collisions with (Entry Test 2007)

A) Electrons

B) Protons

C) Phonons

D) Photon

Q: Decay of one radioactive atom per second is equal to (Entry Test 2007-2010)

A) One curie

B) One Becquerel

C) One half-life

D) None

Q: A radioactive substance has a half-life of 60 minutes. During 3 hours the percentage of material decayed would be (ET 2016)

A) 12.5%

B) 87.5%

C) 8.5%

D) 25.1%

Q: Nuclear fusion at the Sun is increasing the supply of (ET 2015)

A) Hydrogen

B) Helium

C) Nucleons

D) Nucleons

Q: Gamma rays have higher penetrating power than α and β rays due to (ET 2010)

A) No charge

B) Non-material nature

C) Small size

D) Lighter particles

Q: The lifetime of an ordinary excited state is (ET 2010)

A) 10^-13 sec

B) 10^-8 sec

C) 10 sec

D) 1.0 sec