Cosmology

Question 1

Define Redshift

Answer 1

The fractional increase in wavelength OR decrease in frequency; [1 mark]
Due to the source and observer moving away / receding from each other; [1 mark]

Question 2

Doppler effect

Answer 2

The change in frequency / wavelength; [1 mark]
Due to the relative motion; [1 mark]
Between a source of sound / light and an observer; [1 mark]

Question 2

Half-life

Answer 2

the length of time it takes for the activity of an amount of a radioactive substance to halve.

Question 2

Drag coefficient

Answer 2

A measure of how easily an object can move through a fluid (liquid or gas)

Question 3

Moderator

Answer 3

a material used in nuclear reactors to make neutrons move more slowly

Question 4

Oscilloscope

Answer 4

a device used to observe waves and vibrations

Question 5

Sonar

Answer 5

method of using sound waves to detect objects and measure their distance.

Question 5

Stroboscope

Answer 5

apparatus that produces short, bright flashes of light at regular intervals ( that is, at a known frequency, flash per second); the apparatus allows the frequency to be varied; it is used to allow a series of images of a moving object to be captured photographically or to determine the speed of rotating objects.

Question 6

Voltage

Answer 6

amount of energy transferred to each coulomb of charge that passes.