Answer:

is time required to heat to boiling point form initial temperature.
Explanation:
Given:
initial temperature of water, 
time taken to vapourize half a liter of water, 
desity of water, 
So, the givne mass of water, 
enthalpy of vaporization of water, 
specific heat of water, 
Amount of heat required to raise the temperature of given water mass to 100°C:



Now the amount of heat required to vaporize 0.5 kg of water:

where:
mass of water vaporized due to boiling


Now the power rating of the boiler:



Now the time required to heat to boiling point form initial temperature:


When the temperature lowers the plants can freeze and die. One way to prevent that is to cover the plants so they dont freeze
Answer:
(a) 8Ω (b) Ratio = Parra/P8 ohm = 1
Explanation:
Solution
Recall that,
An high-fidelity amplifier has one output for a speaker of resistance of = 8 Ω
Now,
(a) How can two 8-Ω speakers be arranged, when one = 4-Ω speaker, and one =12-Ω speaker
The Upper arm is : 8 ohm, 8 ohm
The Lower arm is : 12 ohm, 4 ohm
The Requirement is = (16 x 16)/(16 + 16) = 8 ohm
(b) compare your arrangement power output of with the power output of a single 8-Ω speaker
The Ratio = Parra/P8 ohm = 1
This might help and it might not:
Gravitation is the acting force between two bodies. On the other hand, gravity is the force occurring between an object and the very big object earth. Every object with some mass exerts the gravitational force on every other object having some mass. This force and its strength depend on the masses of the objects under consideration. Gravity helps to keep the planets to move in their orbit around the sun.
Gravitation is the force of attraction between any two bodies in the universe. In our universe, each object attracts each other with a certain amount of force. The large distance of separation is the main reason for its weak nature.
Gravity is the weakest type of fundamental force in nature. Still, it holds together the entire solar systems and galaxies.
Gravity has the existence with unlimited range.
The slope represents the acceleration