Class 11 Physics Assignment

Physics is based on measurement and mathematical expression of laws. Physical quantities such as force, velocity, energy and charge are measured numerically, and relationships between them are written as equations.

Answer: Because Physics uses measurements and mathematics to describe natural phenomena.

Observation gives information about a phenomenon, but Physics also requires measurement, analysis, hypothesis, experimentation and verification. Without experiments, a conclusion may not be reliable.

Answer: Observation must be supported by measurement and experimental verification.

The observation of falling bodies and planetary motion helped Newton formulate the universal law of gravitation. This law explained both falling objects and motion of planets.

Answer: Falling bodies and planetary motion led to Newton’s law of gravitation.

The main aim of Physics is to discover basic laws of nature and use them to explain different physical phenomena in a simple and unified way.

Answer: To understand and explain nature through basic laws.

Measurement converts observations into numerical data. Without measurement, physical laws cannot be tested accurately or expressed mathematically.

Answer: Measurement makes Physics precise and testable.

The theory must make testable predictions. These predictions must be verified by repeated experiments and observations. If results agree, the theory may be accepted.

Answer: It must be experimentally tested and verified.

A hypothesis is a proposed explanation for a phenomenon. It is not accepted as a law unless it is tested and supported by experiments.

Answer: A tentative explanation that needs experimental verification.

Mathematics gives exact and compact form to physical laws. It helps calculate results and predict future outcomes accurately.

Answer: Mathematical form makes laws precise and predictive.

It means that using physical laws, we can predict future events or unknown results. For example, the motion of satellites can be predicted using gravitational laws.

Answer: Physics can predict outcomes using known laws.

Physics is used in automobile engines, braking systems, aeroplane flight, railway motion and rocket propulsion. These depend on mechanics, thermodynamics and fluid dynamics.

Answer: Aeroplane flight and braking systems are examples.

Physics helps calculate rocket motion, satellite orbits, escape velocity, gravitational effects and communication with spacecraft.

Answer: It provides laws required for rockets, satellites and space missions.

Fundamental forces explain interactions between particles and bodies. They help us understand atoms, nuclei, matter, planets and galaxies.

Answer: They explain all basic interactions in nature.

The motion of planets around the Sun is controlled by gravitational force. The Sun attracts planets and provides the centripetal force for orbital motion.

Answer: Gravitational force.

Electrons are negatively charged and the nucleus is positively charged. The electromagnetic force of attraction keeps electrons bound to the nucleus.

Answer: Electromagnetic force.

Protons and neutrons are held together by strong nuclear force. It is very strong but acts only over very short nuclear distances.

Answer: Strong nuclear force.

Most contact forces such as friction, tension, normal reaction and chemical bonding arise from electromagnetic interactions between atoms and molecules.

Answer: Many everyday forces originate from electromagnetic interactions.

Remaining kinetic energy = Initial kinetic energy − Energy lost
= 600 J − 150 J
= 450 J.

Answer: 450 J.

Useful output = Input energy − Wasted energy
= 1000 J − 250 J
= 750 J.

Answer: 750 J.

Total momentum remains zero. Therefore the other part must have equal momentum in opposite direction.

Answer: 20 kg m/s towards left.

Momentum p = mv
= 5 × 4
= 20 kg m/s.

Answer: 20 kg m/s.

Conservation laws allow us to relate initial and final states without knowing all intermediate details. This makes many problems easier.

Answer: They help solve problems using initial and final values directly.

A law describes a consistent relationship observed in nature, often mathematically. A theory explains why and how a phenomenon occurs using deeper principles.

Answer: A law describes; a theory explains.

Many real systems are complex. Approximations simplify them so that useful results can be obtained without losing the main physical idea.

Answer: To simplify complex situations while keeping essential physics.

A common approximation is treating Earth as a sphere or treating a small object as a point mass when its size is negligible compared with distances involved.

Answer: Treating a small body as a point mass.

Scientific ideas are continuously tested. If new experiments contradict old ideas, the ideas are improved, modified or replaced.

Answer: Science changes according to reliable evidence.

Engineering applies physical laws to design machines, bridges, circuits, engines, communication systems and buildings.

Answer: Engineering uses Physics principles for practical design and technology.

Electricity and magnetism were once considered separate. Maxwell showed that they are connected aspects of one electromagnetic interaction.

Answer: Maxwell unified electricity and magnetism into electromagnetism.

Nuclear Physics explains fission and fusion. Nuclear power plants use fission reactions to produce large amounts of energy.

Answer: It explains nuclear reactions used for energy generation.

Theory provides explanation and prediction, while experiment checks whether the prediction is correct. Both are necessary for scientific progress.

Answer: Theory predicts; experiment verifies.

Physics teaches that natural phenomena are not random; they follow definite laws that can be discovered through observation, measurement and reasoning.

Answer: Nature follows systematic laws that can be understood scientifically.