31000+ Important MCQs for CDS

An isomeric transition is a radioactive decay process that involves emission of a gamma ray from an atom where the nucleus is in an excited metastable state, referred to in its excited state, as a nuclear isomer. The emission of a gamma ray from an excited nuclear state allows the nucleus to lose energy and reach either a lower energy state, sometimes its ground state. In certain cases, the excited nuclear state following a nuclear reaction or other type of radioactive decay, has a half live that is more than 100 to 1000 times longer than the average 10-12 seconds, and this excited state is referred to as a metastable nuclear excited state. Some nuclei are able to stay in this metastable excited state for minutes, hours, days, or occasionally far longer, before undergoing gamma decay, in which they undergo radioactive decay with primary emission of a gamma ray.

While potassium bromate is said to be a Class 2B carcinogenic, which means it may cause cancer, potassium iodate can lead to “thyroid disorders, increase the incidence of autoimmune thyroid it is and increase the risk of thyroid cancer.

Zeolites are used as water softeners, to remove calcium ions from water. Clinoptilolite, a natural zeolite is used to clean radioactive wastes from nuclear power plant. Zeolites act as catalyst and are used in catalytic cracking to break down large organic molecules found in petroleum into the smaller molecules that make up gasoline, a process called catalytic cracking.

Time period T ∝ √l where l is the distance between point of suspension and center of mass of bob and is called effective length.

Neither stationary charges nor charges in uniform motion (steady currents) can be sources of electromagnetic waves. The former produces only electrostatic fields, while the latter produces magnetic fields that, however, do not vary with time. As per Maxwell’s theory, accelerated charges radiate electromagnetic waves.