Monthly Mock Test (January 31) - NEET MCQ

Work required to turn the dipole is given by
W=MB[cosθ_i- cosθ_f]
Here θi is the initial angle made by a dipole with a magnetic field and   is the final angle made by a dipole with a magnetic field.
magnetic moment is normal to the field direction.
so, θ_i=0 and θ_f=90
W = 1.5 × 0.22 [ cos0° - cos90° ]
W = 0.33J
 
magnetic moment is opposite to the field direction.
so, θ_i=0 and θ_f=180
now, W = 1.5 × 0.22 [ cos0° - cos180°]
= 0.33 [ 1 - (-1) ]
= 0.66 J

The earth's magnetic field is Be​ and its horizontal and vertical components are H_e​ and H_v​
cosθ= H_e​​/B_e​
∴cos60^o= (​0.26×10^−4​/ B_e )T
⇒B_e​=(​0.26×10⁻⁴)/ (½)​=0.52×10⁻⁴T=0.52G

Correct Answer :- C

Explanation : Magnetic Moment = Magnetization × Volume

Side of cube = 20 cm

= 0.2 m

= 500 × 0.2 × 0.2 × 0.2

= 4Am²

At null point (and along the axis), earth's magnetic field and bar's magnetic field are opposite in direction.
On the equatorial line, the bar's magnetic field is opposite in direction to its field on the axis. Hence, on the equatorial line, the two fields add up.
As the null points are on the axis of the bar magnet, therefore,
B1= (μ0/4π)(2M/d3)=H
On the equatorial line of magnet at same distance(d), field due to the magnet is 
B2= (μ0/4π)(M/d3)=B1/2=H/2
Therefore, total magnetic field at this point on equatorial line is 
B=B2+H=3H/2=3×0.36G/2=0.54G
 

Correct Answer :- d

Explanation : μ_total = MV

= (8*10⁵)(2*10^-2)

= 6A m²

Magnetic field on the axis of a current loop with magnetic material μtotal is:

B = μ₀ μ_total / (2π(x² + a²)^1/2

B = (4π*10^-7)(6) / [2π(0.1)]

= 1 * 10^-3 T

= 0.001 T

According to the question, the resultant field is inclined at 45o with earth's magnetic field.
tanθ=B_H​​/B
θ=45^o
tanθ=1=B_H​​/B
B_H​=B= μ_o​M​/4πr³
Given, B= 0.42×10⁻⁴T
M=5.25×10⁻²J/T
Therefore,0.42+10⁻⁴=10⁻⁷×[(5.25×10⁻²)/r³]​
r³=12.5×10⁻⁵=125×10⁻⁶
r=5×10⁻²m = 5 cm

When a parametric material comes close to a magnetic field the atoms will align with the magnetic field which causes another magnetic field. Permeability is the total magnetic field divided by the original magnetic field. Increase in temperature makes it harder for the atoms to align which decreases the strength of the second field. This results in a lower total magnetic field (numerator) and thus lower permeability.

A bar magnet may be thought of as a large number of circulating currents in analogy with a solenoid. On cutting a bar magnet in half we get two smaller solenoids with weaker magnetic properties.The field lines remain continuous, emerging from one face of the solenoid and entering into the other face. (i.e. similar magnetic fields). The magnetic moment of a bar magnet is also equal to the magnetic moment of an equivalent solenoid.
 

O. N. of Al = +3
O. N. of B = + 3
[BF₄]^-
[Al(C₂O₃)₃]^3-

Consider werner’s theroy

[Ni⁰(CO)₄]
[Cr³⁺(NH₃)₂][Ni⁴⁺F₆]₃
[Ni²⁺(NH₃)₂][B⁺³F₄]₂
K₄[Ni⁺²(CN)₆]

^–OCN is ambident ligand & it shows linkage isomerism.

[PtBrCl NH₃ Py] Pt²⁺ is dsp² hybridised & hence geometry is square planner & sq. planner complex with four different ligands shows geometrical isomerism.

H₂O is weak field ligand

Alzheimer disease is a neurological disorder in which the death of brain cells causes memory loss and cognitive decline. It is caused in human due to deficiency of acetylcholine.

The gut microbiota can influence the central nervous system through the synthesis of ACh and other neuroactive molecules:

The release of toxic haemozoin by the ruptured RBCs during malarial infection accounts for the recurrence of high fever and chill every 3-4 days.

The first antibiotic was discovered by Alexander Fleming from the fungus Penicilliumnotatum in 1928.

Antibodies in our body are present in the blood in form of glycoproteins. They produce antigens in response to foreign particles to provide immunity against the pathogen.

Memory cells are formed in lymphocytes of WBC. Immunization against the particular disease based on the function of memory cell induced due to mild, heat killed pathogen administrated during immunization.

• Physiological barriers to the entry of microorganisms into the human body are tears in the eyes, saliva in the mouth and HCl in the stomach.
• The enzymes lysozymes are found in tears and saliva and inhibit the synthesis of peptidoglycan present in the cell wall of microorganisms especially eubacteria.
• Disease-causing microorganism enters through different routes into the body. The physiological barrier prevents their entry. Tears act as a physiological barrier for entry of pathogen.

AIDS day is celebrated on December 1 all over the world. Its aim is to create awareness about this dreaded disease.

A tumor enclosed within a capsule is called benign tumor. Benign tumors normally remain confined to their original location and do not spread to other parts of the body and cause little damage.

AIDS can be transmitted from infected person to healthy person through blood transfusion. The most common way of transmission of AIDS is during sexual intercourse with multiple partners without protection.

Cancer cells divide rapidly and hence they are said to be more active with a less prominent nucleus and low-density cytoplasm.

Hence, they get destroyed easily by laser treatment. Moreover, the form lumb in a certain place which can be easily distinguished by the doctors.

Lysergic acid diethylamide is one of the most potent mood changing chemicals manufactured from lysergic acid, which is found in ergot fungus that grow on rye and other grains.

Cirrhosis of liver is caused by the chronic intake of alcohol. Regular consumption of alcohol damages the liver cells. Cirrhosis of liver is a serious condition when normal liver tissue is replaced by scar tissue.

Marijuana, hashish, charas, and ganja contain chemicals called cannabinoids. They are generally, taken as inhalation or oral ingestion to effects cardiovascular system of the body.

Amphetamines is kind of drug which is used as stimulant. It is a strong CNS stimulant that is used in the treatment of ADHD. Lysergic acid dimethyl amide is not a narcotic and heroin is not a psychotropic agent.

A. Invasiveness of a pathogen is its ability to gain entry into a host and grow.

B. Toxigenicity is the power of a pathogen to form toxins capable of damaging host cells.

C. Virulence is the ability of a pathogen to produce disease.

D. Co-operation is a property not exhibited by a pathogen.

Hence, the correct answer is option D: Co-operation