5. The following table
distribution
400
lamps :
gives the
the life time of
of
neon
Life time
less than
1500 - 2000 Less than 2000
f
lop
14
56
14
70
2000 - 500 Less than 2500
2500-3000 less than 3000
60
180
86
216 m. ch
290
3000 - 3500 less than 3500
3500-4000 less than 4000 74
4000 - 4900 less than 450062
4500 - 5000 Less than 5000
852
48
4.00
N=400​