Practice MCQ Questions and answers on Physics-GK

The coil wire in the electric room heater or electric cooking heater is called element.

The composition of electrician solder is Lead-37%, tin-63%.

When the switch is ON, in a tube light choke is nothing but the coil/ballast (inductor) which is used to induce the high voltage across it.

The primary reason that power is transmitted at high voltages is to increase efficiency. As electricity is transmitted over long distances, there are inherent energy losses along the way.

Tungsten is used in electric bulb because it has high melting point and it does not oxidize. Thus tungsten filament does not melt even when a large amount of heat is produced due to passage of current through the filament (via heating effect of current).

In a filament type light bulb most of the electric power consumed appears as Infra-red rays. When electricity flows through the fiber, it heats up. Depending on the filament temperature, the radiation is emitted from the filament.

Nichrome is the most common domestic heating element and is found in many household products. Commonly, items such as toasters, hair dryers and heaters use Nichrome coils to pass electricity and give off heat. Nichrome is made of 80 percent nickel and 20 percent chromium, and its high melting point of 1,400 degrees Celsius. Nichrome is a non-magnetic alloy of nickel, chromium, and often iron, usually used as a resistance wire. Patented in 1905, it is the oldest documented form of resistance heating alloy. A common alloy is 80% nickel and 20% chromium, by mass, but there are many others to accommodate various applications. Due to its relatively high electrical resistivity and resistance to oxidation at high temperatures, it is widely used in electric heating elements, such as in hair dryers, electric ovens, soldering iron, toasters, and even electronic cigarettes.

The inside of the bulb being a vacuum, the outside air rushes in when the bulb is broken. The vibrations of the rushing air molecules produce the sound.

Flemings ''Left hand Rule" is associated with the effect of magnetic field on current.