Answer:
m = 4.5021 kg
Explanation:
given,
Apparent mass of aluminium = 4.5 kg
density of air = 1.29 kg/m³
density of aluminium = 2.7 x 10⁷ kg/m³
true mass of the aluminium = ?
Weight in Vacuum
W = m g
W = ρV g
Air buoyancy acting on aluminium
B = ρ₀V g
Volume is the same in both cases since the volume of the aluminum
displaces an equal amount of volume air.
Apparent weight:
ρV g − ρ₀V g = 4.5 g
ρV − ρ₀V = 4.5
m = ρV
m = 4.5021 kg
Answer:An incandescent light bulb gives only energy of the system in the form of heat. ... The roof of a house is stable but it receives energy from the surroundings and transfers energy through it towards lower temperature side which includes no mass transfer. So, it is best considered as closed system.
Explanation:
My Anonymuos friend, I could not agree more with your statement.
Truer words have rarely if ever been expressed.
Well, we know that the total energy in a closed system remains constant.
The problem with the story of Eva is that she is not in a closed system.
If the dark room were really a closed system, then she could press the
button or turn the switch all day, and the lamp could not light. It needs
electrical energy coming in from somewhere in order to turn on.
Let's say that Eva used her arm muscles to strike a match and light the
candle on the table. Then we would have have food energy, muscle
energy, chemical energy in the match, chemical energy in the candle,
heat and light energy coming out of the candle, heat energy soaking into
her hand, light energy bouncing off of the book and into her eyes ... all
going on during the story, and the sum total of all of them would remain
constant.
Answer:
discrete lines are observed by the spectroscope, the emission of the lamp is of the ATOMIC source
Explanation:
Bulbs can emit light in several ways:
* When the emission is carried out by the heating of its filament, the bulb is called incandescent, in general its spectrum is similar to that of a black body, this is a continuous spectrum with a maximum dependent on the fourth power of the temperature of the filament.
* The emission can be by atomic transitions, in this case there is a discrete spectrum formed by the spectral lines of the material that forms the gas of the lamp, in general for the yellow emission the most used materials are mercury and sodium or a mixture of they.
Consequently, as discrete lines are observed by the spectroscope, the emission of the lamp is of the ATOMIC type
