How do individual molecules move within a solid material______________?
Show answer Hide answer
Answer: D. back and forth like tiny pendulums
Explanation
Molecules in a solid do not translate freely but vibrate back and forth around fixed equilibrium positions like tiny pendulums. Strong intermolecular attractive forces restrict solid molecules from moving past one another while permitting thermal vibrations. This restricted oscillatory motion maintains the definite shape and rigid structural volume characteristic of solid materials. States of matter are distinguished by the kinetic energy and intermolecular spacing of their constituent atoms or molecules. Solid matter possesses high structural rigidity because particles remain locked in an ordered crystalline or amorphous lattice. Thermal energy input increases the amplitude of molecular vibrations without breaking the primary bonding forces holding solids together.
Option A describes random molecular translation typical of gases rather than bound solid structures. Option B suggests haphazard wandering movement characteristic of liquids rather than fixed crystal lattices. Option C proposes circular motion, which does not accurately represent standard atomic lattice oscillation dynamics.
- Subject
- Engineering
- Category
- Mechanical Engineering
- Topic
- —
- Difficulty
- medium
Related questions
Q1. In a petrol engine, M.E.P. initially rises with air-fuel ratio before dropping; within what mixture zone does maximum M.E.P. occur________________?
Show answer Hide answer
Answer: C. rich mixture
Mean effective pressure represents the theoretical constant pressure acting during a power stroke to produce measured engine work. As the air-fuel mixture becomes richer, flame propagation speed and combustion pressure i...
Q2. By what means can the machinability rating of steel be improved___________________?
Show answer Hide answer
Answer: B. phosphorous, lead and sulphur
Machinability of steel is enhanced by adding free-machining additives such as sulfur, phosphorus, and lead, which promote chip breakage. These alloy additions form microscopic inclusions that interrupt continuous chip fo...
Q3. How should elliptical manhole covers be oriented on a pressure vessel shell___________________?
Show answer Hide answer
Answer: B. circumferentially
Cylindrical pressure vessels experience hoop stress that is twice as large as longitudinal stress. Elliptical manhole covers must be oriented so their major axis aligns with hoop stress. This circumferential orientation...
Q4. Which additive acts as the most effective grain growth inhibitor when mixed in minute amounts__________________?
Show answer Hide answer
Answer: B. vanadium
Vanadium forms extremely stable carbides and nitrides that precipitate out along grain boundaries during steel processing. These finely dispersed precipitates physically pin the grain boundaries, preventing them from mig...
Q5. How does the latent heat of steam at elevated pressures compare to its value at standard atmospheric pressure__________________?
Show answer Hide answer
Answer: A. less
At elevated operating pressures, the latent heat of vaporization of steam is lower than its value at standard atmospheric pressure. As system pressure rises toward the critical point, the energy required to vaporize wate...
Q6. What is thermodynamically the most efficient technique for air compression_________________?
Show answer Hide answer
Answer: A. isothermally
Isothermal compression occurs at a constant temperature, minimizing the required work input. Thermodynamically, removing heat during compression prevents excessive temperature spikes. This process eliminates the extra wo...