Most adult sized bicycles these days have aluminium alloy handlebars, or even carbon fiber. Aluminium bars may be anodized, but will usually not be anodized. BMXes, Dutch bikes Townies and cruisers may have steel bars which usually are chromed.
If it's high quality, they would have had a copper layer first, to help the chrome stick to the bar.
Can be anything that's strong enough.
But usually aluminium or steel. Carbon fibre is a possiblility, and even titanium.
Usually rubber or plastic compounds, although leather handles do exist.
Mostly aluminium, Although smaller fittings are most likely steel.
steel
Metals, plastic, maybe even a wooden handle.
On a human-powered bicycle the brake calipers are usually up by the fork crown and at the top of the seat stays. The brake levers are usually on the handle bars
The cast of Yellow Bicycle Handle - 2010 includes: Susan Karsnick
Because to actuate the brake you pull at the brake lever.
a block
Yes.
Bicycle brakes are usually levers
Friction and leverage.
The bicycle was invented using already existing materials, so no new material was developed for the bicycle.
Most spokes are metal, and metals are conductors.
Caliper and Disk brakes
Sure you could, if there were any in production. But since there aren't, you can't. A bicycle is simply too light for the advantages of a EM brake to outweigh the added complexity.