For radioactive decay, we can relate current amount, initial amount, decay constant and time using:
N = No x exp(-λt)
Half-life = ln(2)/λ
λ = ln(2) / 5730
N/No = 80% = 0.8
0.8 = exp( -ln(2)/5730 x t)
t = 1844 years
Answer:
B. Intermolecular forces are hard to overcome
Explanation:
A high boiling point indicates greater inter molecular forces between the molecules of the substance. Inter molecular forces is the force of attraction between the molecules of the substance, which has to be overcome or broken before the substance boils. Example, when water boils, the water molecule (H₂O) will be broken into hydrogen molecule and oxygen molecule.
Therefore, a high boiling point temperature indicates that intermolecular forces of the substance are hard to overcome.
B. Intermolecular forces are hard to overcome
Answer:
Splitting water molecules produces hydrogen gas, which is used to power machines through hydrogen fuel cells. ( B-)
Answer:
f = 3 × 10⁶ Hz
Explanation:
Given data:
Wavelength of wave = 1.0 ×10² m
Frequency = ?
Solution:
Formula:
Speed of light = wavelength× frequency
Frequency = speed of light / wavelength
speed of light = 3× 10⁸ m/s
f = 3× 10⁸ m/s / 1.0 ×10² m
f = 3 × 10⁶ s⁻¹
s⁻¹ = Hz
f = 3 × 10⁶ Hz
