Answer:
Choice A.
A low birth to death ratio
Explanation:
A low birth to death ratio means that people are dying faster than they are being born. This leads to a decreasing population size.
Answer:
1) The power of Niagara Falls is 1.176 × 10⁹ W
2) The number of 15 W LED light bulbs it could power is 78.4 × 10⁶ light bulbs
Explanation:
1) The Niagara falls water mass flow rate = 2,400,000 kg/s
The height of the fall = 50 meters
The gravitational potential energy = Mass (kg) × height (m) × gravity (9.8 m/s²)
The power = The energy converted per second = Mass flow rate (kg/s) × height (m) × gravity (9.8 m/s²)
Therefore;
The power of Niagara Falls= 2,400,000 kg/s × 50 m ×9.8 m/s²= 1.176 × 10⁹ W
The power of Niagara Falls = 1.176 × 10⁹ W
2) The number, n, of 15 W LED light bulbs it could power is given by the relation;
n × 15 W = 1.176 × 10⁹ W
∴ n = 1.176 × 10⁹ W/(15 W) = 78.4 × 10⁶ light bulbs
The number of 15 W LED light bulbs it could power = 78.4 × 10⁶ light bulbs.
C = 4 mol/l
v = 0.5 l
n(NaCl)=cv
n(NaCl) = 4 mol/l · 0.5 l = 2 mol
2 moles of NaCl must be dissolved
Answer:
Yes it is B,D.
Explanation:
Each box represents an element and contains its atomic number, symbol, average atomic mass, and (sometimes) name. The elements are arranged in seven horizontal rows, called periods or series, and 18 vertical columns, called groups.
（c) the color turns deep dark and then at certain level, it turns back to light green.
(d)fastest.
