Physics

Only available on StudyMode
  • Download(s) : 110
  • Published : February 4, 2013
Open Document
Text Preview
1.

This question is about lasers. (a) With reference to the light waves emitted by a laser, state what is meant by the terms (i) monochromatic. ........................................................................................................................... ........................................................................................................................... (1)

(ii)

coherent. ........................................................................................................................... ........................................................................................................................... (1)

(b)

The diagram (not to scale) shows three of the energy levels of a substance used to produce laser light.

The energy of the ground state is E0.

(i)

State what is meant by population inversion. ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... (1)

(ii)

Draw an arrow on the diagram to indicate the transition that results in a population inversion. Label the arrow P. (1)

IB Questionbank Physics

1

(iii)

Draw an arrow on the diagram to indicate the transition that results in a pulse of laser light. Label the arrow L. (1)

(iv)

Deduce that the wavelength of the emitted laser light is 690 nm. ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... (1) (Total 6 marks)

2.

This question is about an astronomical telescope. The diagram (not to scale) shows the arrangement of the two convex lenses in an astronomical telescope in normal adjustment.

The telescope is used to observe a distant star. One of the focal points of the eyepiece lens is labelled FE.

(a)

On the diagram above, (i) label, with the symbol FE, the position of the other focal point of the eyepiece lens. (1)

(ii)

label, with the symbol FO, the position of the focal point of the objective lens that is in between the two lenses. (1)

IB Questionbank Physics

2

(iii)

construct rays to locate the final image of the star.
(3)

(b)

In a particular astronomical telescope, the eyepiece lens has a power of 40 dioptres and the objective lens a power of 0.80 dioptres. Determine the angular magnification of the telescope in normal adjustment. ...................................................................................................................................... ...................................................................................................................................... ...................................................................................................................................... ...................................................................................................................................... ...................................................................................................................................... (2)

(c)

In an astronomical telescope the objective is often made up from a diverging and a converging lens, whereas the aperture of the eyepiece is usually restricted such that only rays close to the principal axis are viewed. State the reasons for this. Objective lens: ............................................................................................................. Eyepiece lens:...
tracking img