It's been a while since I've studied this, but my answers would be:
13. 5730 years. The half-life of a substance is the amount of time it takes for half of it to decay, and, according to the graph, half of the substance remained at 5730 years.
14. 10740 years. According to the graph, only 25% of the carbon remained after 10740 years.
15. 15 atoms. According to the graph, only 12.5% of the carbon remained after 16110 years. 12.5% of 120 atoms is 15 atoms.
16. 1600 atoms. According to the graph, if a sample of carbon is 10740 years old, only 25% of it remains. To find the original amount, multiply the current amount by (100% / 25%), which equals 4. So, 4. 400 atoms * 4 = 1600 atoms is the original amount.
Answer:
The charge passes a given point in the conductor during this time is 9.8 C.
Explanation:
Given that,
Current = 1.4 A
Time = 7.0 sec
We need to calculate the charge during this time
Charge :
Charge is the product of current and time.
In mathematically form,
Where, i = cirrent
t = time
Put the value into the formula
Hence, The charge passes a given point in the conductor during this time is 9.8 C.
Answer: The magnetic field of a bar magnet is strongest at either pole of the magnet. It is equally strong at the north pole compared with the south pole. The force is weaker in the middle of the magnet and halfway between the pole and the center. So it would be D.
upper one :
Each metal atom contributes one or more electrons . Note:-free and mobile electrons are responsible for high thermal and electrical conductivity of metals. metals contain lot of free electrons while nonmetals don't have it. metals conduct electricity due to the presence of free electrons which are absent in non-metals.
down one :
metals are good conductors of both heat and electricity, whereas nonmetals generally cannot conduct heat or electricity. ... Metalloids tend to be shiny like metals but brittle like nonmetals. Because they are brittle, they may chip like glass or crumble to a powder if struck.
