Questions

An Egg is more useful when it is broken than it is not.

In chemistry, the term transition metal has three possible meanings: The IUPAC definition defines a transition metal as "an element whose atom has a partially filled d sub-shell, or which can give rise to cations with an incomplete d sub-shell".

Any of the set of metallic elements occupying a central block (Groups IVB–VIII, IB, and IIB, or 4–12) in the periodic table, e.g. iron, manganese, chromium, and copper. Chemically they show variable valency and a strong tendency to form coordination compounds, and many of their compounds are coloured.

Here in the given options, only iron (Fe) is a transition metal since Strontium is an alkaline earth, arsenic is a metalloid, hydrogen is (normally) a diatomic gas.

Alternating Current (AC) is the current in which flow of current is altered periodically whereas in DC current i.e, direct current the flow of current is only in one direction.

Some of the sources of AC current are :

1. Hydro-electric generators

2. Thermal power generators

3. Nuclear  power generators...