Lower resistivity means higher conductivity: among these materials, the best conductor is silver, therefore it must be the material with lowest resistivity among those. We can also have a look at the value of resistivity of the different materials listed in the problem, to check our answer. The resistivities of the materials are the following:
Wood:

Salt water:

Silver:

Lead:

<span>We see that the material with lowest resistivity among those is silver, therefore the correct answer is silver.</span>
The heat released by the water when it cools down by a temperature difference

is

where
m=432 g is the mass of the water

is the specific heat capacity of water

is the decrease of temperature of the water
Plugging the numbers into the equation, we find

and this is the amount of heat released by the water.
Answer:
The velocity of the wave is 12.5 m/s
Explanation:
The given parameters are;
he frequency of the tuning fork, f = 250 Hz
The distance between successive crests of the wave formed, λ = 5 cm = 0.05 m
The velocity of a wave, v = f × λ
Where;
f = The frequency of the wave
λ = The wavelength of the wave - The distance between crests =
Substituting the known values gives;
v = 250 Hz × 0.05 m = 12.5 m/s
The velocity of the wave, v = 12.5 m/s.
Answer:
Thermocouple, also called thermal junction, thermoelectric thermometer, or thermel, a temperature-measuring device consisting of two wires of different metals joined at each end. One junction is placed where the temperature is to be measured, and the other is kept at a constant lower temperature.
For the part a) we need only the momentum of the box and we have the data to find it.
Momentum is given by,

where clearly, p is the momentum, m the mass of the box and v is the velocity.
Substituting,

For part b) we need an analysis of the situation. We understand that the box on a surface that has no friction will continue to rotate at the same speed previously defined. The box can only stop with friction, so,

<em>It is the same that part a)</em>