Physics Gcse

• What is the half-life of an isotope?

  The half-life of an isotope is the time taken for the number of nuclei in a sample of the isotope to halve
• Exam question: Some scientists have to change theories about the universe. Give the reason why.

  there is new evidence that does not fit into current theory / model
• 1 Tera (t) metre in meters

  1 x 10 12
• 1 Giga (G) meter


  1 x 10 9
• 1 Mega (M) meter

  1 x 10 6
• 1 kilometer (Km) 


  1 x 10 3
• 1 centimeter (cm)


  1 x 10 -2