a) Explain quantization of charge. b) An ion of specific charge \( 4.40 \times 10^7 \text{ C/kg} \) is moving in a circular orbit in a magnetic field…

a) Explain quantization of charge. 

b) An ion of specific charge \( 4.40 \times 10^7 \text{ C/kg} \) is moving in a circular orbit in a magnetic field of flux density 0.4T with velocity of \( 3.52 \times 10^5 \text{ ms}^{-1} \). Calculate the radius of this orbit. 

c) Why are x-rays used in Millikan's oil drop experiment? 

                      OR

a) Define the terms half life and mean life of a radioactive substance. 

b) If 2 gm of a radioactive material having half life period of 50 years disintegrates, find out mean life of the given sample. 

c) Given figure represents decay graph of a radio active sample of half life 10 years. Estimate the value of T₃