Question

if T is mean life time of a radio actives sample then how much time will it take to decay if 75%of the active nuclei present in the sample ?​

Answer 1

A clock which keeps correct time at 20°C, is subjected to 40°C. If coefficient of linear expansion of the pendulum is 12 × 10⁻⁶ per °C. How much will it gain or loose in time?(a) 10.3 seconds/day(b) 20.6 seconds/day(c) 5 seconds/day(d) 20 minutes/day