Physics 20-11-24

What is the Doppler effect and how does it apply to sound waves?

• The Doppler effect only applies to light waves and has no relevance to sound waves.

• The Doppler effect is the phenomenon where sound waves become louder as the source moves away from the observer.

• The Doppler effect is the change in frequency of sound waves due to the relative motion between the source and the observer.

• The Doppler effect is the change in amplitude of sound waves due to temperature variations.

What are systematic errors and how can they affect experimental results?

• Systematic errors are random fluctuations in measurements that do not affect results.

• Systematic errors are consistent inaccuracies in measurements that can lead to biased experimental results.

• Systematic errors can be easily corrected by averaging multiple measurements.

• Systematic errors are only present in theoretical calculations, not in experiments.

Explain the difference between random errors and systematic errors.

• Random errors are unpredictable and vary, while systematic errors are consistent and repeatable.

• Random errors can be corrected with calibration.

• Systematic errors are random and unpredictable.

• Random errors are always larger than systematic errors.

What is the SI unit for measuring force?

• Joule (J)

• Pascal (Pa)

• Watt (W)

• Newton (N)

Differentiate between elastic and plastic deformation.

• Elastic deformation involves breaking bonds; plastic deformation involves stretching bonds.

• Elastic deformation occurs at high temperatures; plastic deformation occurs at low temperatures.

• Elastic deformation is reversible; plastic deformation is permanent.

• Elastic deformation is always permanent; plastic deformation is reversible.

What happens to a material when it undergoes elastic deformation?

• The material becomes stronger and more rigid after deformation.

• The material permanently deforms and does not return to its original shape.

• The material melts and loses its solid form when stress is applied.

• The material temporarily changes shape but returns to its original form when the stress is removed.

Explain how wave frequency changes when the source is moving towards an observer.

• The frequency decreases as the source moves towards the observer.

• The frequency remains constant regardless of the source's movement.

• The frequency fluctuates randomly as the source approaches the observer.

• The frequency increases as the source moves towards the observer.

What is the relationship between wavelength and frequency in wave behavior?

• Wavelength and frequency are inversely related.

• Wavelength and frequency are unrelated.

• Wavelength increases as frequency increases.

• Wavelength and frequency are directly related.

Describe how temperature can affect the deformation of solids.

• Higher temperatures make all solids stronger.

• Temperature influences the deformation of solids by changing their ductility and strength; higher temperatures generally increase ductility and lower temperatures can increase brittleness.

• Temperature has no effect on solid deformation.

• Lower temperatures always increase ductility.

A molecule of mass m travelling horizontally with velocity u hits a vertical wall at right-angles to its velocity. It then rebounds horizontally with the same speed.

What is its change in momentum?

• Zero

• mu

• −mu

• −2mu