IAS Objective Physics Set - III (Read 8 times)

1. Bohr's theory of hydrogen atom did not explain fully
A. diameter of H atom    B. emission spectra
C. ionisation energy    D. the fine structure of even hydrogen spectrum

2. A current loop placed in a non-uniform magnetic field experiences :
A. a force of repulsion    B. a force of attraction
C. a torque but not force    D. a force and a torque

3. For a heavily doped n-type semi-conductor, Fermi-level lies
A. a little below the conduction band    B. a little above the valence band
C. a little inside the valence band    D. at the centre of the band gap

4. Which of the following indicates that the galaxies are receding from us ?
A. Neutron Star    B. White dwarf    C. Black hole    D. Red shift

5. What does it represents?
A. AND    B. NAND   
C. OR    D. NOR

6. In a transistor, the relation between a and b is
A. b = a /(1 - a )    B. b = 1/(1 - a )    C. b = a /(1 + a )    D. b = 1 - a