What is meant by the statement that a laser beam is coherent, mono-chromatic and parallel?

Laser light however contains only one wavelength. This property makes lasers monochromatic, meaning of one color. Another property of lasers is that all the wavelengths are in phase, meaning they wave together. This property is called coherency. Laser light travels in the same direction, parallel to one another.

the answer is ampere

the ampere is used to measure electricity. an ampere is a unit of electric current equal. a unit of measure for the flow of current in a circuit. one ampere is the amount of current flow provided when one volt of electrical pressure is applied against one ohm of resistance.

when jerome paddle in flowing river towards east the net speed of jerome will increase

so the net speed of jerome will be given as

now the speed of paul will be same as it is given as he is running on the ground

so

so here we can say since the speed of jerome is more so he will win the race

now as we know the distance so the time difference is given as

so jerome will reach first and the time difference will be 203.55 s or 3.4 min