Answer:
Gases: Oxygen and Carbon dioxide
Liquids: Water
Solid: Most Metals
We would have to use wind or another source
Answer:
0.34148 m
Explanation:
= Resistivity of tungsten = 
d = Diameter = 0.0018 inch
r = Radius = 

= Temperature coefficient of tungsten = 
Power is given by

We have the equation
![R_2=R_1[1+\alpha(T_2-T_1)]\\\Rightarrow R_1=\dfrac{R_2}{1+\alpha(T_2-T_1)}\\\Rightarrow R_1=\dfrac{144}{1+0.0045(2550-25)}\\\Rightarrow R_1=11.64812\ \Omega](https://tex.z-dn.net/?f=R_2%3DR_1%5B1%2B%5Calpha%28T_2-T_1%29%5D%5C%5C%5CRightarrow%20R_1%3D%5Cdfrac%7BR_2%7D%7B1%2B%5Calpha%28T_2-T_1%29%7D%5C%5C%5CRightarrow%20R_1%3D%5Cdfrac%7B144%7D%7B1%2B0.0045%282550-25%29%7D%5C%5C%5CRightarrow%20R_1%3D11.64812%5C%20%5COmega)
Resistance is given by

The length of the filament is 0.34148 m
Explanation:
A charge alters the space around it. This alteration of space is called the electric field. It is also defined as the electric force acting on a charged particle per unit test charge. It is given by :

Where
F is the electric force, 
The direction of electric field is in the direction of electric force. For a positive charge, the direction of electric field lines are outwards and for a negative charge, the direction of field lines are inwards.
Hence, the correct option is (c) "electric field".