Answer:
The value of total energy needed per minute for the humidifier = 77.78 KJ
Explanation:
Total energy per minute the humidifier required = Energy required to heat water to boiling point) + Energy required to convert liquid water into vapor at the boiling point) ----- (1)
Specific heat of water = 4190 
The heat of vaporization is = 2256 
Mass = 0.030 kg
Energy needed to heat water to boiling point = 
Energy needed to heat water to boiling point = 0.030 × 4.19 × (100 - 20)
Energy (
) = 10.08 KJ
Energy needed to convert liquid water into vapor at the boiling point
= 0.030 × 2256 = 67.68 KJ
Thus the total energy needed E =
+ 
E = 10.08 + 67.68
E = 77.78 KJ
This is the value of total energy needed per minute for the humidifier.
Answer: most effective way is to practice reduce reuse and recycle for utilisation of resources
Explanation:
The electric field at a distance r from the charged particle is given by :

k is electrostatic constant
if r = 2 m, electric field is given by :

If r = 1 m, electric field is given by :

Dividing equation (1) and (2) we get :

So, at a point 1 m from the particle, the electric field is 4 times of the electric field at a point 2 m.
To answer the problem we would be using this formula which isE = hc/L where E is the energy, h is Planck's constant, c is the speed of light and L is the wavelength
L = hc/E = 4.136×10−15 eV·s (2.998x10^8 m/s)/10^4 eV
= 1.240x10^-10 m
= 1.240x10^-1 nm
Answer:

Explanation:
Let's assume that an object is launched straight upward in a gravitational field. Its initial kinetic energy is given by
(1)
where m is the mass and v is the initial speed.
As the object goes higher, its kinetic energy decreases and it is converted into gravitational potential energy, since the total mechanical energy (sum of kinetic and potential energy) must remain constant:

At the highest point of the trajectory, the speed of the object is zero (v=0), so the kinetic energy is also zero (K=0), which means that all the kinetic energy has been converted into potential energy:
(2)
where g is the gravitational acceleration and h is the maximum height of the object.
Due to conservation of energy, we can write that (1) and (2) are equal, so:

from which we can derive an expression for the maximum height reached by the object
