One example is that when their food catches fire in a cooking pot or pan, it is advisable to smother the fire by covering the fire with a blanket rather than douse the fire with water. DOeing the later will only aggravate the fire. Knowledge of basic science dictates that oil and water are immiscible liquids the oil will continue to burn even as the water is poured into the oil. More so, as the water violently evaporates due to the heat, it spreads the burning oil and hence spreads the fire.
Answer:

Explanation:
We know that there is a relation between the speed of light ,frequency and wavelength.This relation can be given as
where v is speed of light
is frequency of light
is wavelength of light
In first case we have given λ=655 nm
so using formula 

Hz
In second case we have wavelength 515 nm so by using above formula


In third case we have wavelength 475 nm
so 

Answer:
angular speed of both the children will be same
Explanation:
Rate of revolution of the merry go round is given as
f = 4.04 rev/min
so here we have

here we know that angular frequency is given as



now this is the angular speed of the disc and this speed will remain same for all points lying on the disc
Angular speed do not depends on the distance from the center but it will be same for all positions of the disc
To solve this problem we will apply the energy conservation theorem for which the work applied on a body must be equivalent to the kinetic energy of this (or vice versa) therefore


Here,
m = mass
= Velocity (Final and initial)
First case) When the particle goes from 10m/s to 20m/s



Second case) When the particle goes from 20m/s to 30m/s



As the mass of the particle is the same, we conclude that more energy is required in the second case than in the first, therefore the correct answer is A.