In which condition, lac operon is switched off?

In E.coli, the lac operon gets switched on when:

What change do we observe in the Galvanometer when the current in the Solenoid coil is switched off?

Right or wrong . If wrong , write the correct sentence : When an electrical rotating fan is switched off it continues to rotate for some time due to inertia of motion .

In medium where E. coli was growing lactose was added, which induced the lac operon. But why does lac operon shut down after some time after addition of lactose in the medium?

In which condition the gene frequency of a population will remain constant ?

In which conditions the gene freqency of a population will remain constant?

Under which conditions of motion between source and observer, Doppler effect is not observed?

When a ceiling fan is switched off, its angular velocity reduces to 50% while it makes 36 rotations. How many more rotations will it make before coming to rest?(Assume uniform angular retardation)

Under which conditions will cyclic photophosphorylation occur?

Answer the following : What are the conditions in which acceleration is produced ?