Which particles are found in an atom's nucleus?
AnswerProtons and neutrons
The nucleus holds protons and neutrons; electrons are outside it.
Science · Facts & stats
Nuclear facts & stats
7 fact-checked facts about nuclear science, each with the reason behind it. 5 more are in today's round and join this page after it closes.
The basics
What powers the Sun?
AnswerNuclear fusion
The Sun fuses hydrogen into helium in its core, releasing huge amounts of energy.
Going deeper
What is the half-life of a radioactive substance?
AnswerThe time for half of its atoms to decay
After one half-life, half of the original radioactive atoms have decayed.
An alpha particle is the same as the nucleus of which element?
AnswerHelium
An alpha particle has two protons and two neutrons, identical to a helium-4 nucleus.
Which uranium isotope is the main fissile fuel in typical nuclear power reactors?
AnswerUranium-235
U-235 fissions easily with slow neutrons; natural uranium is mostly U-238.
Expert level
What is the approximate half-life of carbon-14, used in radiocarbon dating?
Answer5,730 years
Carbon-14 has a half-life of about 5,730 years, useful for dating remains up to around 50,000 years old.
Who discovered the neutron in 1932?
AnswerJames Chadwick
James Chadwick proved the neutron's existence in 1932 and won the 1935 Nobel Prize in Physics.
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