Practice Test - NEET MCQ

Explanation:for electromagnetic induction magnet and coil both may move but relative motion between must be present

Explanation : The coil of galvanometer is wound on a light metal frame. When the coil and frame rotate in the field of the permanent magnet, the eddy current set up in the frame oppose the motion so that the coil returns to zero quickly.

Explanation:A will become positive with respect to B because current  indused is in clockwise direction

e = NBAω = NBA²πn = 8 x 0.5 x 0.09 x 2 x 3.14 x 60 = 136V

From the first law of thermodynamics dQ = dU + dW, so clearly for the isothermal expansion or compression of a real gas where u = f(T) from the first law dU = 0 which means that the entire heat supplied is converted into work but from the second law of thermodynamics we find that in no process can the entire heat supplied can  be converted into work hence in reality some fraction of heat supplied is always used to increase the internal energy of the system.

Extensive variable →H (enthalpy), E (Internal energy) and Mass. Since these variables depend on the amount of substance or volume or size of the system.

As work is a path function rather than a state function, we can easily say that work can often be graphically represented as the area under the PV graph. And as cyclic processes are represented as closed shapes on PV graph it is obvious that they have non zero area and thus work done is non zero.

From the first law of thermodynamics,
we know, dU = dQ - dW ; (work done BY the system is considered +ve)
For an adiabatic process, dQ = 0, and hence, dU = -dW
For an ideal gas expansion, we see that work done
BY the system is +ve (recall the sign convention for work done), i.e., dW > 0.
Therefore, dU is less than 0, and thus, the internal energy decreases.

T_Initial  = t K
Work, W = 9R
Ratio of specific heats, γ = C_p / C_v = 4/3
In an adiabatic process, we have
W = R(T_Final – T_initial) / (1-γ)
9R = R (T_Final – t) / (1 – 4/3)
T_Final – t = 9 (-1/3) = -3
T_Final  = (t-3) K

The correct answer is option D(None of the above)
The given compound is 4-Bromo-3methylheptanal

This is 1-phenyl propan-1-one.

The correct answer is option C
CH_3​CH₂​CONH₂​ (A)⟶ CH₃​ − CH₂ ​− NH₂​ (B)⟶ ​CH_3​ − CH₂ ​− OH
In the above sequence A & B respectively are Br₂​/KOH and HNO₂​
The first step is Hoffmann bromamide degradation reaction in which an amide (propanamide) is converted to an amine  (ethylamine) containing one carbon atom less. The reagent A is bromine in presence of KOH. In the second step, aliphatic primary amine (ethyl amine) reacts with nitrous acid (reagent B) to form aliphatic primary alcohol (ethyl alcohol).
 

Fe + HCl is preferred due to the following reasons:
- Scrap iron i.e Fe is cheap and commercially easily available
- FeCl₂ formed will get hydrolysed and release HCl, so, HCl which is required in the reaction will be produced by itself
- Hence only small amount of HCl is required to initiate the reaction.

Aniline is prepared commercially by the catalytic hydrogenation of nitrobenzene or by the action of ammonia on chlorobenzene. The reduction of nitrobenzene can also be carried out with iron borings in aqueous acid. A primary aromatic amine, aniline is a weak base and forms salts with mineral acids.

Because it produces produced nine plants with round, yellow seeds, three plants with round, green seeds, three plants with wrinkled, yellow seeds and one plant with wrinkled, green seeds.therefore the ratio is 9 : 3 : 3 : 1

As true tall breeding and true dwarf breeding is seen only a single time in F2 generation, and the remaining are hybtid tall...so the ratio becomes 1 : 2 : 2 : 1.

But 1 : 1 is the ratio for only true tall breeding and true dwarf breeding in F2 generation.

A single gene may have two or more phenotypic expressions. The multiple phenotypic effect of a single gene is called pleiotropism. Hence the gene associated with this phenomenon is called Pleiotropic gene.

 Test cross is across made to identify hidden recessive alleles in an individual of unknown genotye. This individual is crossed with one that is homozygous for the allele being investigated (i.e., a homozygous recessive). The homozygous recessive individual may be the parent of the individual being investigated.

• A lac operon consists of one regulatory gene (i) and three structural genes (z, y and a).
• The “i” in regulatory gene is derived from the word “inhibitor”.

The structural gene (z) of the lac operon codes for β-galactosidase. It is responsible for the hydrolysis of polysaccharides. The ‘y’ genes code for permease. It increases the permeability of a cell to β-galactosidase. The ‘a’ genes code for transacetylase.

In figure above, A represent helicase and B represents single strand binding protein. These structures are formed during semiconservative replication of DNA.

Evolution is the gradual change of race due to variation is course of time. It is the history and development of race along with variations. Evolution is a continuous process and takes millions of years to evolve a new species.

Origin of universe is explained by big bang theory. According to this theory, whole universe was concentrated into single sphere. Due to same unknown region, there was explosion in it that forms different galaxies still moving away from each other.

According to abiogenesis theory of origin of life, life originated from non-living matter like gases, inorganic substance and water at particular temperature and pressure.

• Chimpanzee is closely related to man. DNA content and DNA matching are the same in both.
• This similarity is more than 99% with chimpanzee whereas 94% with a gibbon.

Darwin judged the fitness of an individual by number of offspring the individual produce in particular niche. More the viable offspring formed the more fit the organism in that surrounding.