Q.

For bacterial growth in a cell culture, growth law is very similar to the law of radioactive decay. Which of the following graphs is most suitable to represent bacterial colony growth

Where N – Number of Bacteria at any time, N0 – Initial number of Bacteria.            [2025]

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Ans.

(1)

Initial number of bacteria = N0

Number of bacteria at time t = N

Rate of increase of bacteria = dNdt

As bacteria grow by first order:

dNdt=kN

dNN=kdt

Integrate both sides:

N0NdNN=0tkdt

[lnN]N0N=k[t]0t

N=N0ekt

This is exponential growth.