IB Physics Phase Difference

/

A tutorial sheet on phase difference is given below.

  1. What does the term "in phase" mean?
  2. What does the term "180 degrees out of phase" mean?
  3. How do we define phase difference?
  4. Are points on a progressive wave all in phase?
  5. A progressive wave has a wavelength of 1.0 m. What is the phase difference between two points on the wave that are 0.8 m apart?
  6. Are points on a standing wave on a string all in phase?
  7. The wavelength of the standing wave on a string is 1.0 m. What is the phase difference between two points on the string that are 0.8 m apart?
  8. In an AC transformer are the primary and secondary voltages in phase?
  9. In an AC transformer are the primary and secondary currents in phase?
  10. For application to transformer problems see S J Osmond, Physics Education, vol 17, no 5, Sep 1982 p236

IB Physics Why is it Hotter in Summer than in Winter?

/

A tutorial sheet of true/false questions on this work in topic 8 is given below.

  1. Summer occurs when the Earth in its orbit is closest to the Sun.
  2. The angle of the Sun above the horizon causes less energy to strike the surface of the Earth in winter.
  3. The low Sun angle causes a bundle of Sun's rays to be spread over a larger area of the surface of the Earth in winter than summer.
  4. The Sun is lower above the horizon in winter causing a lower amount of energy to enter the atmosphere.
  5. The Sun is above the horizon for a shorter time in winter reducing the time for a bundle of Sun's rays to heat the surface of the Earth.
  6. The atmosphere is not heated by the Sun but by reflected longer wavelength radiation from the Earth. In winter each square metre of surface reflects less energy and so the surrounding atmosphere is at a lower temperature.
  7. The variation in the maximum angle made by the Sun above the horizon during the year is due to the inclination of the Earth's spin axis at 66.5° to the plane of the Earth's orbit.
  8. People at the equator experience 12 hours of night and day every day of the year.
  9. Sunset in Melbourne on January 1 is before sunset in Sydney.
  10. Sunrise in Melbourne on January 1 is after sunrise in Sydney.
  11. See Roy L Bishop, Journal of the Royal Astronomical Society of Canada vol 87 No 5 p346 1993