20600Cal
Explanation:
Given parameters:
Mass of water = 319.5g
Initial temperature = 35.7°C
Final temperature = 100°C
Unknown:
Calories needed to heat the water = ?
Solution:
The calories is the amount of heat added to the water. This can be determined using;
H = m c Ф
c = specific heat capacity of water = 4.186J/g°C
H is the amount of heat
Ф is the change in temperature
H = m c (Ф₂ - Ф₁)
H = 319.5 x 4.186 x (100 - 35.7) = 85996.56J
Now;
1kilocalorie = 4184J
85996.56J to kCal;
= 20.6kCal = 20600Cal
learn more:
Specific heat brainly.com/question/3032746
#learnwithBrainly
The answer to both is D. Here's why:
For the first, whenever motion changes in a magnetic field, it causes electrons to move. Electricity, which is needed to power a lightbulb, is just a term for movement of these electrons. Electrons aren't created, they're always there in the wire. It's just that the permanent magnet gets them to move, which produces electricity.
For the second, it is very similar to the first. A magnet won't cause any electric current at rest, it always requires motion in order to produce an electric current. If you keep both of those in mind, it should help in the future. Hope this helps!