Answer:
1083.3kg/m
³
Explanation:
Given parameters:
Mass of aluminium ball = 3.4kg
Apparent mass of ball = 2.1kg
Unknown:
Density of the liquid = ?
Solution:
Density is is the mass per unit volume of any give substance;
Density = 
Now, we must understand that the apparent weight of the aluminium is the part of its weight supported by the fluid;
Pl = 
Pl = density of liquid
Ml = mass of liquid
Vl = volume of liquid
Mass of liquid = Mal - Mapparent
Mal = mass of aluminium
The volume of liquid displaced is the same as the volume of the aluminium according to Archimedes's principle;
Ml = Pl x Vl
Val = Vl
Val volume of aluminium
Vl = volume of liquid
****
Pal = 
Val = 
Val = volume of aluminium
Mal = mass of aluminium
Pal = density of aluminium
*****
Since the Val = Vl
Ml = Pl x 
Since
Ml = Mal - Mapparent
Mal - Mapparent = Pl x 
Pal = density of aluminium = 2712 kg/m
³
3.4 - 2.1 = Pl x 
1.3 = Pl x 0.00123
Pl = 1083.3kg/m
³
From Literature:
The amount of energy in the photons is given by this equation:
E = hf
where E = energy
h = Planck's constant = 6.63 * 10^-34 Joule seconds
f = frequency of the light, Hz
Given:
E= 3.00 eV and Planck's constant
To solve for the frequency, E = 3.00 eV
1 electronvolt = 1.60218 x 10^-19 Joules
3 * 1.60218 x 10^-19 Joules = 6.63 * 10^-34 Joule seconds * f
f = 7.25 x 10^14 /second or hertz
Therefore, the threshold frequency of the material is 7.25 x 10^14 Hertz.
Answer:
Day and night on Earth are equal.
Explanation:
Vernal means fresh or new like the spring. The vernal equinox, because it signals the beginning of spring. On this day, the Sun is exactly above the Equator and day and night are of equal length. In the northern hemisphere, the vernal equinox is around March 20 or 21 when the Sun crosses the celestial equator going north while in the southern hemisphere, the vernal equinox is around September 22 or 23 when the Sun moves south across the celestial equator.