About how long ago do scientists believe the universe began?
13,600 million years
3 of 18
Why is the light from distant galaxies red-shifted?
They are moving away from us.
4 of 18
What is one of the disadvantages of space telescopes?
They are difficult to maintain.
5 of 18
Isotopes of an element are different from normal atoms of the same element because they have a different number of ...
... neutrons.
6 of 18
What happens when a nucleus splits?
Radiation is released.
7 of 18
What particles are found in the nucleus of an atom?
Protons and neutrons
8 of 18
A teacher used a Geiger counter to measure the radiation of a radioactive rock. Wrapping the rock in paper and aluminium foil had no effect on the count rate. What does this tell us about the rock?
The rock emits gamma radiation.
9 of 18
How do we change the rate of emission of radiation from a radioactive object?
We can't change the rate
10 of 18
What happens to photographic film when it is exposed to radiation and then developed?
It goes darker.
11 of 18
What do radiation badges do?
They monitor the radiation dose a worker receives.
12 of 18
The half-life of an isotope is 1 hour. How long will it take for the count rate to fall to one-quarter of the starting rate?
2 hours
13 of 18
What happens to the half-life of a substance when it is put into a freezer?
It stays the same.
14 of 18
How do signals travel through optical fibres?
As infra-red radiation
15 of 18
What is a signal that varies continuously in frequency called?
An analogue signal
16 of 18
How many different states are there in a digital signal?
Two
17 of 18
The distance from the crest of one wave to the crest of the next wave is called:
The Wavelenght
18 of 18
Other cards in this set
Card 2
Front
Ultraviolet light can be used:
Back
For fluorescent lights
Card 3
Front
About how long ago do scientists believe the universe began?
Back
Card 4
Front
Why is the light from distant galaxies red-shifted?
Back
Card 5
Front
What is one of the disadvantages of space telescopes?
Comments
Report
Report
Report
Report
Report