General Science Questions and Answers

Answer: D

The most ancient geological formations are dated by the uranium–lead method, which is good to about 4,500 million years.

Uranium-238 decays to lead-206 with a half-life of 4,470 million years, so the ratio of the two dates the rock. Carbon-14, with a half-life of 5,730 years, is useless beyond about 50,000 years and works only on once-living material.

Answer: D

German silver is an alloy of copper, zinc and nickel - typically 60:20:20 - and contains no silver at all.

It is named for its silvery appearance, and is used for tableware, keys of musical instruments and resistance wire.

Answer: A

The theory that living things arise only from other living things is biogenesis.

It replaced the older belief in abiogenesis, or spontaneous generation, which Redi, Spallanzani and finally Pasteur disproved - Pasteur's swan-necked flask experiment of 1859 settled the question.

Answer: D

Monazite is the chief ore of thorium, a phosphate mineral of the rare earths that carries thorium as an impurity.

The beach sands of Kerala and Tamil Nadu are among the world's richest monazite deposits, which is why India's long-term nuclear programme is built around thorium.