KE = (1/2)mv2
v2 = 2KE/m
v = (2KE/m)1/2
l = h/mv or v = h/ml
Therefore, h/ml = (2KE/m)1/2
Multiply both sides by mc;
hmc/ml = hc/l = (2KE/m)1/2mc
E = hc/l = (2Kem)1/2c
= [2(6.00X10-22)(9.11X10-31)]1/23.0X108
= 9.92X10-18 J as before.
Notice that the value of Planck's constant h was not needed.

Return to Self Test 2