Practice Test - NEET MCQ

Since Potential difference between two points in equipotential surfaces is zero, the work done between two points in equipotential surface is also zero.

Definition based

Potential Energy of a System with One Point Charge

• Definition of Potential Energy: Potential energy is the energy stored in an object due to its position or configuration in a system.


• Potential Energy of a Point Charge: In the case of a system containing only one point charge, the potential energy of the system is considered to be zero.


• Explanation: When there is only one point charge in a system, there is no other charge or external force interacting with it to create potential energy. Therefore, the potential energy of a single point charge is considered to be zero.

This is why the correct answer is A: Zero.

We want the Voltage difference V_AB.
let A and B be open and not connected to any thing.
There is a current that flows from cell of larger emf to the cell of small emf.
Call that current as  I Amperes.

1.25 V - 0.75 V - I * R2 - I * R1 = 0

I = 0.5 / (R1+R2)
V_AB =  -0.75 - I * R2 =  - 0.75 - 0.5 * R2 / (R1+R2)

= - (0.75 R1 + 1.25 R2) / (R1+R2)

= - ().75 * 1 + 1.25 * 1) / (1 + 1)  volts

=  - 1 volts

1. Current: This is a general term for the flow of electric charge. It can refer to any type of charge flow, not specifically electrons.

2. Electronic current: This specifically refers to the flow of electrons through a conductor.

3. Conventional current: This is the flow of positive charge and is considered to flow from the positive side to the negative side of a power source. Historically, this was defined before the discovery of electrons, so it is opposite to the direction of electron flow.

4. Photonic current: This is not a standard term in electrical engineering or physics. It might refer to currents related to photons in some contexts, but it is not related to the flow of electrons.

So, if you are referring to the flow of electrons specifically, electronic current is the accurate term.

In a p-type semiconductor, the holes are the majority carriers, while the electrons are the minority carriers. A p-type semiconductor is obtained when trivalent atoms, such as aluminium, are doped in silicon atoms.

1001=1x2³+0x2²+0x2¹+1x2⁰=9
For binary numbers, the digit at the extreme right is referred to as least significant bit (LSB) and the left- most digit is called the most significant bit (MSB). Hence in binary 10010, the most significant bit is 1.
 

Open chain compounds or acyclic compounds are otherwise called as aliphatic compounds.

Cyclopropane is a ring (cyclic) compound and hence it does not come with the examples of open chain compounds.

Pyridine is heterocyclic aromatic compound. Whereas naphthalene and aniline are benzenoid aromatic compounds and tropolone is a non-benzenoid aromatic compound.

Termination is the last step. So there shouldn't be any free radical atom remaining. In first option there is Cl• remaining it can't be termination step.The steps in free radical halogenation are as

Free radical bromination reaction is highly selective, occurs mainly at the carbon where most stable free radical is formed.
We know that the stability of free radical is in the order,
Tertiary radical > Secondary radical > Primary radical
In (a), (b) and (c), the bromination occurs at secondary carbon whereas in (d) the bromination occurs at tertiary carbon. Since, tertiary radicals are more stable than secondary radical the major product of monobromination of ethyl cyclohexane is (d).
The stability of tertiary radical is due to the higher number of α−Hygrogens which give more hyperconjugation effect than secondary.

Correct Answer :- b

Explanation : The 2o hydrogens are 20 times more reactive than the 1o ones.

Bromination in the presence of light is done by free radical mechanism. The radical on the carbon chain is formed where the radical is most stable. We can’t put radical on the ring as the aromaticity of the ring will be lost. So, it should be put either on the CH₃. However, the CH₃ which is attached to NO₂ ring will not bear stable radical as NO will decrease the stability of radical.(NO₂ is an electron withdrawing group). So the only position is the other CH₃ in option d. There also we have stability due to resonance.

Sickle cell anaemia is a blood disorder inherited from parents in which the Red blood cells become rigid and sickle-shaped which may lead to different health issues such as anaemia, swelling in the hands and feet, bacterial infections and stroke.

It is an autosomal disorder linked to the recessive alleles.

It has not been eliminated from the African population because it provides immunity against malaria.

Falciparum malaria is the most prevalent malaria in the African continent which is responsible for deaths in this region.

People with sickle cell anaemia are less vulnerable to falciparum malaria.

So, the correct answer is 'It provides immunity against malaria'

Yellow fever is caused by a RNA virus of genus Flavivirus. This virus is transmitted by mosquito, Aedesaegypti in human beings.

Hey fever or Allergic rhinitis is inflammation of nasal airways. It occurs when an allergen is inhaled by an individual with sensitive immune system.

Common cold and AIDS are viral disease caused by rhinovirus and HIV virus respectively.

• Early detection of cancer is essential as it allows the disease to be treated successfully in many cases.
• Cancer detection is based on biopsy and histopathological studies of the tissue and the blood and bone marrow tests for increased cell counts in the case of leukaemias.

The primary and secondary immune response are carried out with the help of two special types of lymphocytes present in our blood called B-lymphocytes and T-lymphocytes.

Inflammation at the spot of insect bit is result of chemical released by the body such as histamine and kinins in response to chemical released by insect in the body.

The treatment of snake bite by anit-venom is an example of artificial acquired passive immunity. Anti-venom neutralize the effect of venom in the body.

Saccharomyces cerevisiae is also known as baker’s yeast. This yeast is used for fermenting wheat flour after it is kneaded. Similarly, the dough which is used for making bread is also fermented using baker’s yeast.

The dough which is used for making foods such as dosa and idli is fermented by using bacteria like Streptococcus. The puffed-up appearance of this dough is due to the production of CO₂ gas.

• Both statements 1 and 2 are correct. A small amount of curd added to the fresh milk as inoculum or starter contains millions of lab, which at suitable temperatures multiply, thus converting milk to curd.
• It improves its nutritional quality by increasing vitamin B₁₂. In our stomach too, the lab plays a very beneficial role in checking disease-causing microbes.

Rennet is extracted from the stomach of the calf and is used to prepare cottage cheese.

LAB stands for Lactic acid bacteria. Indian curd is prepared from both skimmed and cream milk by inoculating the milk with lactic acid bacteria.

Large holes in Swiss cheese are formed by the CO2 produced (causing holes) by a bacterium called Propionibacterium shermanii.

In the preparation of idli batter, the batter is fermented using bacteria or yeast. During fermentation, CO₂ bubbles which are released get trapped in the gluten, thus making idli soft and puffy.

• Both a and r are true and r is the correct explanation of a the dough used for making bread is fermented by saccharomyces cerevisiae or commonly called baker’s yeast.
• CO₂ released during the process of fermentation gives a puffy appearance to a dough. It is used to make foods like idli, dosa, bread, etc.