Telegram group: T.me/BBCNOUN ====== PHY307 ====== 1. Bravais lattice consists of __________ space lattices. Eleven Twelve Thirteen --->> Fourteen 2. Which of the following theories cannot be explained by classical theory? Electron theory Lorentz theory --->> Photo-electric effect Classical free electron theory 3. What does the conductivity of metals depend upon? The nature of the material --->> Number of free electrons Resistance of the metal Number of electrons 4. What is the atomic packing factor of BCC structure? 0.54 --->> 0.68 0.74 0.96 5. The crystal lattice has a _________ arrangement. One-dimensional Two-dimensional --->> Three-dimensional Four-dimensional 6. Which of the following theories can be adopted to rectify the drawbacks of classical theory? Compton theory --->> Quantum theory Band theory Electron theory 7. The smallest portion of the lattice is known as __________ Lattice structure Lattice point Bravais crystal --->> Unit cell 8. What is the coordination number of a simple cubic structure? --->> 6 8 10 12 9. A unit cell that contains lattice points only at the corners is known as _________ --->> Primitive unit cell Secondary unit cell Layered unit cell Derived unit cell 10. What happens to the free electrons when an electric field is applied? They move randomly and collide with each other They move in the direction of the field They remain stable --->> They move in the direction opposite to that of the field