CIE Physics Paper-1: Specimen Questions 106 - 107 of 109
Question number: 106
A small amount of a radioactive isotope contains 72 billion unstable nuclei. The half-life of the isotope is 4 hours. How many unstable nuclei would remain after 12 hours?
The life time of nuclei is can be calculated as,
Here are given,
Question number: 107
Three rays of light fall on a converging lens as shown.
Which diagram shows the path of the rays after passing through the lens?
When parallel rays incident on the converging lens, they will reflected and converged at a point another side of the lens. The distance from the converging lens to intersecting point is equal to focal length of the lens. This proper arrangement is shown in choice C.