MCQ
Smart Materials MCQ - Practice Questions with Answers
Solve 99 Smart Materials questions for RAS/RPSC preparation.
Practice questions
Q1Consider the following statements about ferroelectric and piezoelectric materials: 1. Ferroelectrics are a subset of piezoelectrics with a polar crystal structure. 2. Ferroelectrics possess spontaneous polarization that can be reoriented by an electric field. 3. Nitride perovskites are described as well known, while oxide perovskites are described as much less known. 4. NLR notes that these materials are important for 5G and 6G telecommunications and are promising for energy-efficient nonvolatile memory. Which of the statements given above are correct?
Statements 1, 2 and 4 are correct. NLR describes ferroelectrics as a subset of piezoelectrics with spontaneous polarization reorientable by electric field, and notes relevance to 5G/6G and nonvolatile memory. Statement 3 reverses the source: oxide perovskites are well known; nitride perovskites are less known.
Q2Consider the following statements about dielectric and piezoelectric ceramics: 1. Capacitors store electric energy in the form of an electric field between separated electrodes. 2. Dielectrics are good conductors of electricity. 3. Ceramic materials serve as the dielectric in more than 90 percent of all capacitors. Which of the statements given above are correct?
Statement 1 is correct: capacitors store energy as an electric field between separated electrodes. Statement 2 is false because dielectrics are poor, not good, conductors. Statement 3 is correct: Britannica states that more than 90 percent of capacitors use ceramic material as the dielectric.
Q3Consider the following statements about barium titanate in capacitor dielectric and piezoelectric ceramics: 1. More than 90 percent of all capacitors are produced with ceramic materials serving as the dielectric. 2. Most ceramic capacitor dielectrics are made of barium titanate and related perovskite compounds. 3. Below about 120°C, barium titanate changes to a tetragonal structure as ions shift from cubic positions. 4. Ferroelectricity is described as irrelevant to the utility of barium titanate as a dielectric material. Which of the statements given above are correct?
Statements 1, 2 and 3 are correct from Britannica. Statement 4 is false because Britannica ferroelectricity is the key to barium titanate's utility as a dielectric material.
Q4Consider the following statements about smart oxide materials: 1. Missing oxygen atoms can create spaces and active sites that help ion movement. 2. Ion movement in such a smart oxide can trigger electronic changes linked with visible charge indication. 3. The cited CeNS smart oxide derives its charge-indication ability from immobilising ions completely. 4. The cited mechanism treats missing oxygen atoms as unrelated to charge storage. Which of the statements given above are correct?
Statements 1 and 2 are correct: ties missing oxygen atoms to spaces, active sites, ion movement, electronic changes and visible charge indication. Statement 3 is false because the mechanism depends on ion movement, not complete immobilisation. Statement 4 is false because missing oxygen atoms are central to the cited mechanism.
Q5Consider the following statements about Smart Materials: 1. NASA links material fatigue with repetitive stress. 2. SMASH technology begins by adding shape-memory wire to metal alloys. 3. NASA stated that spacecraft far from Earth would easily have access to a repair shop. Which of the statements given above are correct?
Statements 1 and 2 are correct: NASA describes fatigue as damage under repetitive stress and says SMASH begins with adding shape-memory wire. Statement 3 is false because NASA says a repair shop would not be an option for spacecraft far from Earth.
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6Consider the following statements about smart actuators in NPTEL's smart-materials lecture: 1. Electric field is linked with piezoelectric or electrostrictive actuator devices. 2. Magnetic field is linked with magnetostrictive and magnetorheological-fluid actuator devices. 3. Heat is listed with shape memory alloy and shape memory polymer actuator devices. Which of the statements given above are correct?
7Consider the following statements about chromogenic and self-repairing smart materials: 1. Electrochromic materials change colour or opacity with applied voltage. 2. Thermochromic materials change colour depending on temperature. 3. Photochromic materials change colour in response to light. 4. Self-healing materials require complete external replacement and therefore do not expand material lifetime. Which of the statements given above are correct?
8Consider the following statements about piezoelectric ceramics: 1. Many piezoelectric devices are made from the same ceramic materials as capacitor dielectrics. 2. Piezoelectric ceramics generate voltage mainly when exposed to a magnetic field. 3. Piezoelectricity involves electric charges appearing on certain nonconducting crystals under mechanical pressure. Which of the statements given above are correct?
9Consider the following statements about photochromic materials: 1. In photochromic compounds, the coloured state can be formed by radiation of a certain wavelength. 2. A photochromic compound may revert to a colourless state in the dark or under radiation of a different wavelength. 3. Photochromism is defined by permanent one-way colour change with no reversibility. 4. Some photochromic glasses use silver halide crystals dispersed in the glass melt. Which of the statements given above are correct?
10Consider the following statements about smart materials used in smart structures: 1. Piezoelectric materials are among commonly used smart materials in smart structures. 2. Electro-rheological fluids change viscosity in the presence of an applied electric field. 3. Electro-rheological fluids are defined by viscosity change under a magnetic field alone. Which of the statements given above are correct?
11Consider the following statements about magnetorheological materials: 1. Magnetorheological materials are smart materials whose mechanical properties can be altered in a controlled fashion by an external magnetic field. 2. Magnetorheological materials traditionally include fluids, elastomers and foams. 3. Magnetorheological materials are defined by colour change under ultraviolet light rather than by magnetic-field response. 4. The cited review focuses on magnetorheological fluids but excludes yielding, flow and viscoelastic behaviour. Which of the statements given above are correct?
12Consider the following statements about Smart Materials: 1. The CeNS smart oxide was reported to have excellent cycling stability of 10000 charge-discharge cycles. 2. As a supercapacitor electrode, it exhibited a specific capacitance of 234 farads per gram at 5 amperes per gram. 3. The PIB release said the device failed to power any display or light source. Which of the statements given above are correct?
13Consider the following statements about electrochromic smart windows: 1. They change colour in response to a small electrical stimulus. 2. They can block both visible and near-infrared light. 3. Their commercial limitation has mainly been the unusually low cost of tungsten oxide and lithium-based electrolytes. Which of the statements given above are correct?
14Consider the following statements about thermochromic materials: 1. Thermochromism is the ability of a substance to change colour due to a change in temperature. 2. Liquid crystals and leuco dyes are two basic approaches used for thermochromic colour change. 3. Thermochromic inks or dyes permanently change colour only when exposed to a magnetic field. Which of the statements given above are correct?
15Consider the following statements about shape-memory smart materials: 1. Shape memory is the ability to return to an original shape after deformation. 2. The transformation can be controlled through temperature, magnetic field, electric field, or light. 3. Shape-memory alloys and polymers can recover original shape after large deformation through temperature or stress changes. 4. Nitinol is cited as an example of an electrochromic material, not a shape-memory material. Which of the statements given above are correct?