Initial speed of an α-particle inside a tube of length 4m is 1 kms-1. If it is accelerated in the tube and comes out with a speed of 9 kms-1, then the time for which the particle remains inside the tube is

Given, initial speed, u = 1 kms-1 = 1000 ms-1Final speed, v = 9 kms-1 = 9000 ms-1By using the relation, v2 = u2 + 2as                (9000)2=(1000)2+2×a×4⇒a=107 ms-2∴    The time for which the particle remains in the tube                     v = u + at ⇒  t=v-ua=9000-1000107=8×10-4 s