Answer:
(a) = $34.123
(b) = $8.532
(c) Additional cost of fluorescent bulb is justified
Explanation:
Cost of electricity = $0.17 per kW·h
(a) For a 100 watt bulb which is the same as 100/1000 or 0.1 kW, the cost per hour =
0.1 × 0.17 = $0.017/h
and for 5.5 hours = 0.017×5.5 = $0.0935
The annual cost, which is 365 days, we have
Annual cost = $0.0935 × 365 = $34.123
(b) For the energy efficient 25-watt bulb, we have
25/1000 = 0.025kW
Power cost per annum =
0.025kW×$0.17 per kW·h×5.5×365 = $8.532
(c) Total cost of incandescent bulb = $0.89 total cost of using the incandescent bulb is $34.123 + $0.89 = $35.02
Total cost of using the energy efficient fluorescent bulb is about $3.49
Total cost of using the energy efficient bulb = $8.532 + $3.49 = $12.02
Total cost of incandescent bulb = $35.02 while total cost of energy efficient bulb is = $12.02
$12.02 <$35.02
Additional cost of fluorescent bulb is justified
Answer:
This is an example of a physical change because the ice cubes began to melt.
This is an example of a physical change because the ice cubes began to melt.
Explanation:
The above is the right answer to the question about the dissolution of the whole mixture mentioned in the excerpts above.
Answer:
Explanation:
Plantae Animalia Archaebacteria and Animalia Protista and Eubacteria . Protista and Eubacteria kingdom(s) include organisms that are autotrophic or heterotrophic
Answer:
The right answer is "3 g".
Explanation:
Given:
Initial mass substance,
By using the relation between half lives and amount of substances will be:
⇒ 
Thus, the above is the correct answer.
Answer:
Option C = electron
Explanation:
Electrons are responsible for the production of colored light.
Electron:
The electron is subatomic particle that revolve around outside the nucleus and has negligible mass. It has a negative charge.
Symbol= e-
Mass= 9.10938356×10⁻³¹ Kg
It was discovered by j. j. Thomson in 1897 during the study of cathode ray properties.
How electrons produce the colored light:
Excitation:
When the energy is provided to the atom the electrons by absorbing the energy jump to the higher energy levels. This process is called excitation. The amount of energy absorbed by the electron is exactly equal to the energy difference of orbits.
De-excitation:
When the excited electron fall back to the lower energy levels the energy is released in the form of radiations. this energy is exactly equal to the energy difference between the orbits. The characteristics bright colors are due to the these emitted radiations. These emitted radiations can be seen if they are fall in the visible region of spectrum.
Other process may involve,
Fluorescence:
In fluorescence the energy is absorbed by the electron having shorter wavelength and high energy usually of U.V region. The process of absorbing the light occur in a very short period of time i.e. 10 ∧-15 sec. During the fluorescence the spin of electron not changed.
The electron is then de-excited by emitting the light in visible and IR region. This process of de-excitation occur in a time period of 10∧-9 sec.
Phosphorescence:
In phosphorescence the electron also goes to the excitation to the higher level by absorbing the U.V radiations. In case of Phosphorescence the transition back to the lower energy level occur very slowly and the spin pf electron also change.
