The unstable isotope 234Th decays by ? emission with a half-life of 24.5 days. The initial decay rate of the sample was 9.9 × 1013 Bq. (1 u = 1.6605 x 10-27 kg)
(a) What mass of 234Th was initially present?
(b) What is the decay rate after 68 days?
(a) 0.12 g (b) 1.4 x 1013 Bq
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Indicate whether the statement is true or false
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What will be an ideal response?
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What will be an ideal response?
The light from Polaris is 24.2 times less intense than the light received from Sirius. Which star is the truly brighter star, that is, emitting more visual light at its surface?
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