Answer : The time passed in years is 20.7 years.
Explanation :
Half-life = 28.1 years
First we have to calculate the rate constant, we use the formula :
Now we have to calculate the time passed.
Expression for rate law for first order kinetics is given by:
where,
k = rate constant = 
t = time passed by the sample = ?
a = initial amount of the reactant = 1.00 g
a - x = amount left after decay process = 0.600 g
Now put all the given values in above equation, we get
Therefore, the time passed in years is 20.7 years.
Answer:
When thermal energy is added to a substance, its temperature increases, which can change its state from solid to liquid (melting), liquid to gas (vaporization), or solid to gas (sublimation).
Explanation:
1. Learners are engaged by scientifically oriented questions.
2. Learners give priority to evidence, allowing them to develop and
evaluate explanations that address scientifically-oriented questions.
3. earners formulate explanations form evidence to address scientifically
oriented question
4. Learners evaluate their explanations in light of alternative explanations,
particularly those reflecting scientific understanding.
5. Learners communicate and justify their proposed explanations.
The 5kg object 5m/s 1 m off the ground
Answer:
D) Fusion requires high temperatures and pressures, so how have they reduced the energy cost for it?
Explanation:
Fusion requires high temperatures and pressure for initiation of reaction . There is no chain reaction in it so there is no problem of controlling the problem . On the other hand , the reaction tends to stop as soon as temperature goes down due to heat getting dissipated . There is no problem of fuel as its fuel is deuterium which is present in nature in large amount . The question which is pertinent is that the cost involved in attaining so high temperature is very high so is it cost effective to produce energy by incurring so much of cost . Producing energy by using so much of energy in the beginning appears to be preposterous.
