Covalent bond is formed when atoms share electrons.
Hope this helps you.
conduction : a spoon resting in a cup of tea gets hot
convection: water warming on the stove
Radiation: The sun warming the earth
Answer:
Mass of original sample = 100 g
Explanation:
Half life of cesium-137 = 30.17 years
Where, k is rate constant
So,
The rate constant, k = 0.02297 year⁻¹
Time = 90.6 years
Using integrated rate law for first order kinetics as:
![[A_t]=[A_0]e^{-kt}](https://tex.z-dn.net/?f=%5BA_t%5D%3D%5BA_0%5De%5E%7B-kt%7D)
Where,
![[A_t]](https://tex.z-dn.net/?f=%5BA_t%5D)
is the concentration at time t
![[A_0]](https://tex.z-dn.net/?f=%5BA_0%5D)
is the initial concentration
Initial concentration = ?
Final concentration = 12.5 grams
Applying in the above equation, we get that:-
![12.5\ g=[A_0]e^{-0.02297\times 90.6}](https://tex.z-dn.net/?f=12.5%5C%20g%3D%5BA_0%5De%5E%7B-0.02297%5Ctimes%2090.6%7D)
![[A_0]=\frac{12.5}{e^{-0.02297\times 90.6}}\ g=100\ g](https://tex.z-dn.net/?f=%5BA_0%5D%3D%5Cfrac%7B12.5%7D%7Be%5E%7B-0.02297%5Ctimes%2090.6%7D%7D%5C%20g%3D100%5C%20g)
<u>Mass of original sample = 100 g</u>
Answer:
6.533 × 10^-21J
Explanation:
The energy of the microwave photon can be calculated using:
E = hf
Where;
E = energy of photon (J)
h = Planck's constant (6.626 × 10^-34 J/s)
f = frequency (9.86 x 10^12 Hz)
Hence, E = hf
E = 6.626 × 10^-34 × 9.86 x 10^12
E = 65.33 × 10^(-34 + 12)
E = 65.33 × 10^(-22)
E = 6.533 × 10^-21J
The energy of the microwave photon is
6.533 × 10^-21J
The answer is A
Mark Brainliest ☺☻
