Question 1: Electrical resistance is a measure of how much a material opposes the flow of electric current. In nanotechnology, tiny structures like nanowires and nanoribbons are used to build electronic components. The resistance of these structures influences their performance and energy efficiency.

Answer: Resistance is a measure of opposition to current flow; in nanotech, it affects device performance.

Question 1: Define electrical resistance and name the unit in which it is measured.

Answer: Electrical resistance is the opposition to current flow, measured in ohms (Ω).

Question 2: Explain how the resistance of a nanowire might differ from that of a bulk wire made of the same material.

Answer: Nanowires typically have higher resistance due to increased surface effects and quantum phenomena at small scales.

Question 1: A nanoribbon made of copper has a length of 2 micrometers and a cross-sectional area of 50 square nanometers. Given that the resistivity of copper is 1.68 x 10^-8 Ω·m, calculate its resistance.

Answer: Resistance R = (resistivity * length) / cross-sectional area = (1.68 x 10^-8 Ω·m * 2 x 10^-6 m) / (50 x 10^-18 m^2) = 0.672 Ω

Question 2: If the same nanoribbon's resistance increases to 1.34 Ω when its length is increased to 4 micrometers, what is the resistivity of the material? (Assume cross-sectional area remains the same.)

Answer: Resistivity ρ = R * A / L = 1.34 Ω * 50 x 10^-18 m^2 / 4 x 10^-6 m = 1.675 x 10^-8 Ω·m

Question 1: Describe a simple experiment to measure the resistance of a nanowire. Include the key variables to control and safety precautions.

Answer: The experiment involves connecting the nanowire in a circuit with a multimeter to measure voltage and current. Variables include temperature and contact quality. Safety precautions include handling nanomaterials with gloves and proper ventilation to avoid inhalation of particles.

Question 1: A research team observes that when a nanowire made of sulfur is cooled from room temperature to cryogenic temperatures, its resistance drops significantly. Explain the scientific reason for this change.

Answer: Cooling reduces thermal vibrations in the material, decreasing resistance; in sulfur nanowires, this enhances conductivity at low temperatures.

Question 2: Discuss how resistance at the nanoscale can impact the development of ultra-efficient electronic devices.

Answer: At the nanoscale, resistance influences energy loss and heat generation. Managing resistance is crucial for creating faster, smaller, and more energy-efficient electronic components, as high resistance can lead to power inefficiencies and device overheating.

Question 1: How does the resistance of nanowires influence the design of nanoelectronic circuits used in medical sensors?

Answer: Lower resistance in nanowires allows for faster signal transmission and lower power consumption, making medical sensors more sensitive and energy-efficient.

Question 2: Explain why controlling resistance at the nanoscale is important for developing sustainable energy solutions such as nanoscale solar cells.

Answer: Controlling resistance ensures minimal energy loss and maximizes efficiency in nanoscale solar cells. Good resistance management leads to better charge transfer, higher power output, and longer device lifespan, contributing to sustainable energy solutions.