NEET Test 81

Copper is mainly extracted from copper pyrites. After the concentration of its ore by the froth flotation process, the ore is roasted in a current of air to remove arsenic, antimony, and much sulphur.

The ore is then mixed with a little coke and sand and smelted in a water-jacketed blast furnace. The minor reactions that occurred during roasting continue here. Ferrous oxide combines with sand to form a fusible slag.

The slag obtained during the extraction of copper from copper pyrites is composed of FeSiO₃.

Triticum aestivum is the correct scientific name of wheat-derived by binominal nomenclature. 

Common wheat (Triticum aestivum), also known as bread wheat, is a cultivated wheat species. About 95% of the wheat produced worldwide is common wheat it is the most widely grown of all crops and the cereal with the highest monetary yield.

Hence, the correct option is (B).

A man fired bullet n times in t seconds of mass M=m×n

Now we have been given a force of 144 N.

Apply the concept of Impulse,

I=F⋅Δt= change in momentum =Mv

Here, M=m×n

F.Δt=mnv

Put value in the above equation, we get

144×1=0.04×n×1200

Solve for n, where n= number of bullets fired in one second.

144 / 1200×0.04=n

The number of bullets fired per second is,

n=3

Hence, the correct option is (A).

Longitudinal waves involve changes in the volume and density of the medium. Since all media can sustain compressive stress, longitudinal waves can be transmitted through all three types of media.

Hence, the correct option is (D).

Genetic Engineering Appraisal Committee (GEAC) is the apex body for approval of genetically modified crops in India.

The Genetic Engineering Appraisal Committee (GEAC) is the apex body that allows for commercial release of GM crops. In 2002, the Genetic Engineering Appraisal Committee (GEAC) had allowed the commercial release of Bt cotton. More than 95 percent of the country's cotton area has since then come under Bt cotton.

Hence, the correct option is (B).

Marasmus is a disorder caused by a deficiency of food or protein. Marasmus occurs in infants below 1 year of age when they do not get sufficient mother's milk or weaning diet. Such infants are often provided with very diluted cow or buffalo milk. Marasmus babies have emaciated bodies with shriveled appearance, thin face, sunken eyes, wrinkled thin and dry skin, protruding ribs, reduced digestion, and frequent diarrhea.

Hence, the correct option is (D).

A patient brought to a hospital with myocardial infarction is normally immediately given streptokinase.

Streptokinase is given to the patients with acute myocardial infarction in adults. It helps in the elysis of intracoronary thrombi, the improvement of ventricular function and thereby reduce the mortality caused by infarction.

Hence, the correct option is (B).

In free radical polymerisation which is chain growth in nature, the monomers must be very pure. In case, some impurities are present, they will act as inhibitors. The polymerisation may not be complete and the polymers with shorter chain length may result.

The monomers used in addition polymerisation through free radical should be very pure because the traces of impurities act like inhibitors resulting in short-chain polymers.
Hence, the correct option is (A).