NEET Unit Test - 7 - NEET MCQ

Electromagnetic waves vary in wavelength and frequency. Longer wavelength electromagnetic waves have lower frequencies, and shorter wavelength waves have higher frequencies. Higher frequency waves have more energy.

An oscillator is a circuit which produces a continuous, repeated, alternating waveform without any input. Oscillators basically convert unidirectional current flow from a DC source into an alternating waveform which is of the desired frequency, as decided by its circuit components.

Ultrasound waves are a type of a sound wave which is longitudinal in nature while others are electromagnetic waves because they are transverse in nature.

According to the law of reflection, the angle of incidence and angle of reflection are equal. Both these angles are measured with respect to a line normal to the reflection surface. If I understand the question correctly, the incident ray makes an angle of 60 degrees with the mirror surface, then the angle of incidence can be calculated as:

Angle of incidence = 90 - angle made with the mirror surface

= 90 - 60 = 30 degrees.

Since, angle of incidence = angle of reflection = 30 degrees.

The incident ray will have an angle of reflection of 30 degrees (made with a surface normal to the mirror surface).

The reflected ray will make an angle of 60 degrees (90 - 30 degrees) with the mirror surface.

Given that,
The distance of object from plane mirror D=100cm
So, initial distance of image and object
=100−(−100)
=200cm
Now, object approaches the mirror with the speed=v=5cm/s  
So, distance travelled by object in 6 sec
D=5×6
D=30cm
At this instant,
Distance between mirror and object
D=100−30
D=70cm
Now, the distance between image and object is
D=70−(−70)
D=140cm
Hence, the distance between the object and its image is 140 cm.
 

Kirchhoff’s explained that amplitude of secondary wavelets is proportional to (1+ cos q), where q is the angle between the ray at the point of consideration and direction of secondary wavelets. In the backward direction q = 180°; so 1 + cos q = 0; so their secondary wavelets do not proceed backward.

Hence assertion and both are true and the reason properly explains the assertion.

The Particle Model of emission and absorption is based on the idea that light is composed of discrete particles called photons, and these photons carry quantized energy. This model helps us understand how atoms and molecules interact with light by either emitting or absorbing photons during electronic transitions.

Here,
Aperture, a = 4 mm = 4 × 10-3 m
Wavelength, λ = 400 nm = 400 × 10-9 m = 4 × 10-7 m 

Ray optics is good approximation upto distances equal to Fresnel's distance (ZF).
Fresnel's distance is given by,

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

Werner’s coordination theory describes primary and secondary valencies in coordination compounds:

Thus, statements 2, 3, and 4 are correct.

Answer: A

[Pt(NH₃)₄]Cl₄ → 5 ions
[Pt(NH₃)₂Cl₄] → 0 ions
[Pt(NH₃)₄Cl₂]Cl₂ → 3 ions

Allyl bromide (I) is most reactive among the given halides as pi bonds from allylic position stabilises the transition state. Vinyl iodide (II) is least reactive due to partial double bond character. Electron withdrawing inductive effect of CH₃O^- increases reactivity of (IV) over (III)

The correct answer is Option D.
As HBr in the presence of a peroxide follows antimarkonikoff rule where the negative group should attach to the carbon having less no of hydrogen atoms.

The correct answer is option D

where, X=Cl or Br.
This reaction is known as the Finkelstein reaction. Finkelstein's reaction is used to prepare alkyl iodides starting from alkyl chlorides and alkyl bromides.

Here, again carbon is not chiral in nature.
So, only one alcohol is chiral in nature

Since the product of oxidation reacts with phenyl hydrazine, it is a carbonyl compound. Since it does not answer silver mirror test, it must be a ketone. Ketones are produced by the oxidation of secondary alcohols. So the compound X is isopropyl alcohol

Since monochlorinated compound is formed so that menas all the hydrogens are same.

(CH₃)₃C−O−CH₃ gives (CH₃)₃C−I and CH₃OH on treatment with HI. The reaction occurs by SN1 mechanism.

Carboxylic acids are more acidic than phenols as the carboxylate ion, the conjugate base of carboxylic acid is stabilized by two equivalent resonance structures. Thus, the negative charge is delocalized effectively. However, in phenols, negative charge is less effectively delocalized over oxygen atom and carbon atoms in phenoxide ion.

Protein encoding gene expressed in heterologous host is called as recombinant protein. Protein encoding genes are commonly described as structural or regulatory. Structural gene encodes enzymes and structural protein.

Fermentation is defined more from the point of view of engineers. They see fermentation as the cultivation of high amount of microorganisms and biotransformation being carried out in special vessels called fermenter or bioreactors.

The enzyme used for breaking or lysis of bacterial cells is lysozyme. It helps in the breakdown of carbohydrates found in a bacterial cell. It is also found in tears.

Use of genetically modified crops may increase crop production many times without use of chemicals and fertilizers. Gene coding form higher nutrient and resistance to disease can be incorporated in crop.

Transgenic animals are used to study the toxicity effects of certain chemical in which animals are made to carry gene which make them more sensitive to toxic substance and exposed to toxic substance to be studied.

An important objective of biotechnology in the area of agriculture is to produce pest-resistant varieties of plants.

The attribute that is characteristic of a population and not an individual organism is the sex ratio. While an individual organism is either male or female, a population has a sex ratio that represents the proportion of males to females within the population. This attribute is specific to populations and provides insights into the demographics and reproductive dynamics of the population as a whole.

Option b) "Sex ratio" is the correct answer because it accurately identifies an attribute that is characteristic of populations.

Natural selection operates on the population level to evolve desired traits. While individual organisms have to cope with changes in their environment, it is at the population level that natural selection acts to shape the genetic composition and traits of the population over time.

Population ecology, links ecology to population genetics and evolution. It is at the population level that variations in traits occur due to genetic diversity and interactions with the environment. Individuals with traits that confer advantages in survival, reproduction, and adaptation are more likely to pass on those traits to the next generation through interbreeding.

An age pyramid with a wide base and narrow top indicates a population that is growing rapidly.

In an age pyramid, the width of each age group represents the proportion or percentage of individuals in that specific age group. A wide base indicates a larger population of young individuals, while a narrow top indicates a smaller population of older individuals.

When the base of an age pyramid is wide and the subsequent age groups gradually decrease in width towards the top, it suggests that there is a higher proportion of young individuals compared to older individuals. This is indicative of a population that is growing rapidly because there is a high birth rate.

A population's birth rate refers to the number of births per capita. A population has birth rates and death rates, and these rates are expressed as changes in numbers (increase or decrease) with respect to members of the population.

To calculate the birth rate, the number of births is divided by the population size or the number of individuals in the population. The birth rate per capita provides a measure of the average number of births per individual in the population.