GATE Core Subject Knowledge & Technical Concepts 1 — Questions and Answers
Question 1: Which law explains the relationship between voltage, current, and resistance?
- Newton's Law
- Ohm's Law (Correct answer)
- Kirchhoff's Law
- Hooke's Law
Correct answer: Ohm's Law
Ohm's Law describes the fundamental relationship between voltage (V), current (I), and resistance (R) in an electrical circuit. It states that the current flowing through a conductor is directly proportional to the voltage across it and inversely proportional to its resistance. This relationship is mathematically expressed as V = IR, making it essential for electrical engineering and circuit analysis.
Question 2: What unit is used to measure electrical resistance?
- Volt
- Ampere
- Ohm (Correct answer)
- Watt
Correct answer: Ohm
The Ohm (Ω) is the standard unit of electrical resistance in the International System of Units (SI). Electrical resistance quantifies how much a material opposes the flow of electric current. This unit is named after Georg Simon Ohm, who formulated the law that defines the relationship between voltage, current, and resistance.
Question 3: Which mechanical property measures a material's resistance to deformation?
- Thermal conductivity
- Young’s Modulus (Correct answer)
- Density
- Viscosity
Correct answer: Young’s Modulus
Young's Modulus, also known as the elastic modulus, is a mechanical property that measures a material's stiffness or its resistance to elastic deformation under stress. It quantifies the ratio of stress (force per unit area) to strain (proportional deformation). A higher Young's Modulus indicates a material that is more rigid and less prone to deformation under load.
Question 4: What does Bernoulli’s principle describe?
- Thermal expansion
- Fluid dynamics (Correct answer)
- Electrical conduction
- Nuclear fission
Correct answer: Fluid dynamics
Bernoulli's principle is a fundamental concept in fluid dynamics, which is the study of fluids in motion. It describes the inverse relationship between the speed of a fluid and its pressure or potential energy. Specifically, it states that an increase in fluid speed occurs simultaneously with a decrease in static pressure or a decrease in the fluid's potential energy, explaining phenomena like aerodynamic lift.
Question 5: Which field studies the behavior of forces on structures?
- Fluid mechanics
- Thermodynamics
- Structural mechanics (Correct answer)
- Quantum physics
Correct answer: Structural mechanics
Structural mechanics is a specialized field within applied mechanics that focuses on analyzing the behavior of physical structures and their components under various loads and forces. It investigates how structures deform, experience stress, and strain to ensure their stability, strength, and rigidity. This discipline is crucial for the design and analysis of buildings, bridges, and other engineered systems.
Question 6: Which quantity is conserved in all chemical reactions?
- Volume
- Mass (Correct answer)
- Density
- Temperature
Correct answer: Mass
The Law of Conservation of Mass states that mass is neither created nor destroyed in any chemical reaction or physical transformation within an isolated system. This means that the total mass of the reactants before a chemical reaction must always equal the total mass of the products after the reaction. It is a foundational principle in chemistry, ensuring that atoms are merely rearranged, not lost or gained.
Question 7: Which of the following is an example of a semiconductor material?
- Copper
- Aluminum
- Silicon (Correct answer)
- Iron
Correct answer: Silicon
Silicon is a prime example of a semiconductor material, meaning its electrical conductivity lies between that of a good conductor (like copper) and an insulator (like glass). Its unique electronic properties allow its conductivity to be precisely controlled through doping, making it indispensable for manufacturing transistors, integrated circuits, and nearly all modern electronic devices. This makes silicon the backbone of the digital age.
Question 8: What phenomenon explains why a pencil appears bent in water?
- Reflection
- Diffraction
- Refraction (Correct answer)
- Absorption
Correct answer: Refraction
Refraction is the phenomenon where light bends as it passes from one transparent medium to another, such as from air into water. This bending occurs because light changes speed when it enters a medium with a different optical density. When a pencil is partially submerged in water, the light rays from the submerged part bend differently than those from the part in air, causing the pencil to appear bent or displaced.
Question 9: In thermodynamics, what is an isolated system?
- Exchanges energy only
- Exchanges matter only
- No exchange of energy or matter (Correct answer)
- Exchanges both energy and matter
Correct answer: No exchange of energy or matter
In thermodynamics, an isolated system is a theoretical concept referring to a system that does not exchange either energy (in the form of heat or work) or matter with its surroundings. It is completely sealed off from its environment, making it a crucial model for understanding fundamental thermodynamic principles like the conservation of energy. While perfectly isolated systems are difficult to achieve in reality, the concept is vital for theoretical analysis.
GATE Core Subject Knowledge & Technical Concepts 1
Which law explains the relationship between voltage, current, and resistance?