Explanation:
1.
Given parameters:
Frequency of the radiation = 8.4 x 10¹⁴Hz
Unknown:
Energy of the wave = ?
Solution:
The energy of a wave is given by the expression below;
E = hf
E is the energy
h is the Planck's constant = 6.63 x 10⁻³⁴m²kg/s
f is the frequency
Now insert the parameters and solve;
E = 6.63 x 10⁻³⁴m²kg/s x 8.4 x 10¹⁴Hz
E = 5.57 x 10¹ x 10⁻²⁰J
E = 5.57 x 10⁻¹⁹J
2.
Given parameters:
Wavelength = 2.13 x 10⁻¹³m
Unknown:
Frequency of the wave = ?
Solution:
The frequency of a wave can be determined using the expression;
C = f∧
C is the speed of light = 3 x 10⁸m/s
f is the frequency
∧ is the wavelength
f = 
= 
= 1.41 x 10²¹hz
Answer:- 0.88
Solution:- Masses of silver and copper metals are given and we are asked to calculate the percentage of silver in the alloy.
mass percent of Ag = 
Mass of Ag = 17.6 g
mass of Cu = 2.40 g
mass of alloy = 17.6 g + 2.40 g = 20.0 g
Let's plug in the values in the formula:
mass percentage of Ag = 
mass percentage of Ag = 88%
So, the mass percentage of silver in sterling silver is 88% and in decimal form it is 0.88.
<span>Physical change, heat caused this.
Water molecules that only vibrate are in solid form. If heat energy is added, the molecules will speed up their vibrations until they can break loose from the organized pattern of a solid and begin to slide over each other, changing to liquid state. If more heat energy is added, the molecules will speed up more and move randomly in all directions as a gas/vapor. Removing heat energy will reverse these changes.
</span>
Answer is:
7.8 lb of 21% aluminum and 33.2 ib of <span>
42% aluminum.</span>
ω₁<span> = 21% ÷ 100% = 0.21.
ω</span>₂<span> = 42% ÷ 100% = 0.42.
ω</span>₃<span> = 38% ÷ 100% = 0.38.
</span>m₁ = ?.
m₂<span> = ?.
</span>m₃ = m₁ + m₂<span>.
</span>m₃ = 41 pounds.
m₁ = 41 lb - m₂<span>.
ω</span>₁ · m₁ + ω₂ ·m₂ = ω₃ · m₃.
0.21 · (41 lb -
m₂) + 0.42 · m₂ = 0.38 · 41 lb.
8.61 lb - 0.21m₂ + 0.42m₂ = 15.58 lb.
0.21m₂ = 6.97 lb.
m₂ = 6.97 lb ÷ 0.21.
m₂ = 33.2 lb.
m₁ = 41 lb - 33.2 lb.
m₁<span> = 7.8 lb.</span>
