Questions

silver is the best conductor of electricity.

When compared to remaining 3 metals, as Silver having more number of free electrons in its valency shell it is the good conductor of electricity.

Conductors Thermal Conductivity @ 25degree C

Silver --- 429
Copper --- 401
Gold --- 310
Aluminium --- 250

Personal flotation devices (PFDs), have life span upto it is damaged. Hence, When it has a torn strap you should discard a PFD.

In dealing with a coil spring the spring constant will depend on the stiffness of the spring material, the thicknessof the wire from which the spring is wound and, diameterof the turns of the coil, the number of turns per unit length and the overall length of the spring.

A Dice has 6 faces with 1 - 6 number of dots one on each side.

So in total 1 + 2 + 3 + 4 + 5 + 6 = 21 dots resembles as eyes.