How much work is required to separate the two charges infinitely away from each other?

Two points charges +10muC and -10muC are separated by a distance of 40 cm in air. How much work is required to separated the two charges infinitely away from each other?

No interference pattern is detected when two coherent sources are infinitely close to each other. Why?

How roughage and concentrate differ from each other ?

How do nucleus and ganglion differ from each other?

State the relation between work, charge and potential difference for an electric circuit. Calculate the potential difference between the two terminals of a battery if 100 J of work is required to transfer 20 C of charge from one terminal of the battery to the other.

What are primary and secondary cell? How do they differ from each other?

Which type of charges attract each other?