A certain material is in a room at 25°C. If the absolute temperature (K) of the material is tripled, its resistance doubles. (Water freezes at 273 K.) What is the value for α, the temperature coefficient of resistivity?

The temperature coefficient of resistivity is 0.001689 /°C

Explanation:

Given initial temperature = 25°C = 25 + 273 = 298 k

The final temperature = Three times = 3

Resistance at =  

Resistance at ()= double resistance at = 2  

The resistance of a body can be obtained when given the above parameters with the expression below;

...............................1

Inputting the parameters into equation 1 we have;

2   =  

isolating α we have;

α = 1/(2 x 298 k)

α = 1/596

α = 0.001678 /K = 0.001689 /°C (change in temperature is the same at both centigrade and kelvin scale.

Therefore the temperature coefficient of resistivity is

0.001689 /°C

here we know that ball will drop down by total distance 3.2 m

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now using kinematics

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so speed of the ball will be

laticia draws the diagram below to show earth’s magnetic field.

answer

the arrows to the right of earth should point up.