Answer : The area of the floor in the unit of square feet is, 228.6 square feet
Explanation :
1 yard = 3 feet
Now squaring on both the side, we get
1 square yard = 9 square feet
As, 1 square yard = 9 square feet
As, 25.4 square yard = (9 × 25.4) = 228.6 square feet
Therefore, the area of the floor in the unit of square feet is, 228.6 square feet
Answer:
D
Explanation:
A and C are physical changes, while B is a solution, only D is a chemical reaction.
Henri Becquerel is the first scientist who discover evidence of radioactivity.
Maria Curie is one of the most famous scientists in the world who invented the word "radioactivity". She discovered that radioactive materials gave out rays and discovered two elements: polonium and radium, which are extraordinary active.
Answer:
See explanation below
Explanation:
To solve this problem, we need to use the expression of half life decay of concentration (or mass) which is the following:
m = m₀e^-kt (1)
In this case, k will be the constant rate of this element. This is calculated using the following expression:
k = ln2/t₁/₂ (2)
Let's calculate the value of k first:
k = ln2/2.7 = 0.2567 d⁻¹
Now, we can use the expression (1) to calculate the remaining mass:
m = 8.1 * e^(-0.2567 * 2.6)
m = 8.1 * e^(-0.6674)
m = 8.1 * 0.51303
m = 4.16 mg remaining
