Answer: A crest is the highest point the medium rises to and a trough is the lowest point the medium sinks to. It is also a point on the wave where the displacement of the medium is at a maximum.
Answer:
7.2g
Explanation:
From the expression of latent heat of steam, we have
Heat supplied by steam = Heat gain water + Heat gain by calorimeter
mathematically,
+ 
=
+
L=specific latent heat of water(steam)=2268J/g
=specific heat capacity=4.2J/gK
=specific heat capacity of calorimeter =0.9J/gk
=280g
=38g
α=change in temperature
=(40-25)=15
=(40-25)=15
=(100-40)=60
Note: the temperature of the calorimeter is the temperature of it content.
From the equation, we can make 
the subject of formula
Hence
Hence the amount of steam needed is 7.2g
Answer
Voltage is how fast the electrons flow. Power is a use of voltage times the volumes of electrons. The higher the voltage the more power you have with the same current.
I'm actually going ahead in the book (DC Circuits) so this isn't really homework but I figured the tag was appropriate....the name of the chapter is Ohm's Law and Watt's Law.
<span>Problem: Calculate the power dissipated in the load resistor, R, for each of the circuits.Circuit (a): V = 10V; I = 100mA; R = ?; Since I know
V and
I use formula
P = IV: P = IV = (100mA)(10V) = 1 W.</span>
The next question is what I'm not sure about:
Question: What is the power in the circuit (a) above if the voltage is doubled? (Hint: Consider the effect on current).
What I did initially was: P = IV = (100mA)(2V) = 2 W
But then I looked at the answer and it said 4 W, then I looked at the Hint again. Then I remembered in the book early on it said "If the voltage increases across a resistor, current will increase."
So question is: When solving problems I have to increase (or decrease) current (I) every time voltage (V) is increased (decreased) in a problem, right? How about the other way around, when increasing current (I), you need to increase voltage (V). I'm pretty sure that's how they got 4 W, but want to make sure before I head to the next section of the book.
P = IV = (200mA)(2V) = 4 W
