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(D) Laws of inheritance

Law of dominance, law of segregation and law of independent assortment come under Mendel’s laws of inheritance.

Sense of taste (gustation): The sense of taste and smell work closely together. If we cannot smell something we cannot taste it either. One reason why we cannot taste (or smell) food well with a common cold is that with the nasal passages inflamed and coated with thick mucus layer the smell receptors are practically nonfunctional. The receptor cells for taste are located in taste buds. Humans have about 10,000 taste buds. The majority of taste buds are located in pockets around the papillae (peg-like projections of the mucous membrane) on the surface and sides of the tongue, but there are some on the surface of the pharynx and the larynx. Each taste bud contains about 40 specialized receptor cells or gustatory cells, many more supporting cells and some basal cells that replace the worn out cells of the taste buds. Unlike the receptors for smell, that are modified sensory neurons, the receptor cells for taste are not neurons, but rather specialized cells with slender microvilli on their outer ends. The microvilli protrude into the surrounding fluids through a narrow opening called the taste pore. Dissolved chemicals contacting the microvilli bind to specific receptor present on the microvilli, thereby depolarizing the cell. The dendrites of the associated sensory neurons coil intimately around the receptor cells and synapse with them so that, when a receptor cell is stimulated and depolarized, it releases neurotransmitter which leads to the generation of an action potential in the associated sensory neuron. Each dendrite receives signals from several receptor cells within the taste bud. Nerve fibers emerging from the taste buds pass to the brain stem. From here the nerve impulse is relayed to the taste centre in the cerebral cortex of the brain that perceives the taste sensation.

Normally our taste sensations are complicated mixture of qualities. In humans, there are four basic taste senses: sweet, sour, salt, and bitter. The receptors for these four basic tastes have their areas of greatest concentration on different parts of the tongue: sweet and salty on the front bitter on the back, and sour on the sides. A few substances stimulate only one of the four types of receptors, but most stimulate two, three, or all four types to varying degrees. The sensation and flavour of the food we experience are thus produced by a combination of these four basic sensations, modified by accompanying sensations of smell, texture and temperature.

Correct answer is B.

Out of the 7 pairs of characters, wrinkled or round character was restricted to seeds and not to the leaves. Mendel did not consider any leaf character.

Difference between Homozygous and Heterozygous:

The structural classification of neurons depends upon the number of dendrites extending from the cell body. 

(i) Multipolar neurons have one axon and several dendrites; the majority of neurons in the spinal cord and brain are multipolar. 

(ii) Bipolar neurons have only two processes: a single dendrite and an axon. Biopolar neurons are found in the sense organs-and in the retina of the eye and in olfactory cells. 

(iii) Unipolar neurons lack dendrites and have a single axon, and are also sensory neurons.

We sense the changes in our environment (both internal and external) with the help of special sensory receptors. These environmental changes, called stimuli, once detected by the special sensory cells, are conveyed to the brain in the form of nerve impulses. The meaning of each stimulus is interpreted in the brain and appropriate order is sent to the body parts for its appropriate response to ensure well being.

Acetylcholine: 

(i) The neurotransmitter acetylcholine is released at all neuromuscular junctions between motor neurons and skeleton muscle cell. 

(ii) It is also released in synapses between pre-ganglionic and post-ganglionic in the autonomic nervous system, and at certain synapses between neurons in the central nervous system.

Difference between Dominant and Recessive character:

Hind Brain: It consists of three regions: pons, cerebellum, and medulla oblongata. 

(i) Pons is band of nerve fibers that lies between medulla oblongata and midbrain. It connects the lateral parts of cerebellar hemisphere together. 

(ii) Cerebellum is large and well-developed part of hindbrain. It is located below the posterior sides of cerebral hemispheres and above the medulla oblongata. It is responsible for maintaining posture and equilibrium of the body. 

(iii) Medulla oblongata is the posterior and simplest part of the brain. It is located beneath the cerebellum. Its lower end extends in the form of spinal cord and leaves the skull through foramen magnum.

(i) In the posterior part of the medulla oblongata, the grey matter is internal and white mater is external. 

(ii) In the anterior part of medulla oblongata grey and white matters are irregularly intermingled. 

(iii) In the remaining part of the brain grey matter is external and white mater is internal.

(D) Green coloured pod and rounded seed

Green coloured pod and rounded seed is dominant character according to Mendel.

(D) TT, Tt, tt

The phenotypes obtained from growing 190 grains of Jowar are 140 tall and 50 dwarf. This approximately equal to 3 : 1 ratio. Hence, this will be F₂ generation and there will be 3 genotypes and two phenotypes. The genotypes will be homozygous tall, heterozygous tall and homozygous dwarf, i.e. TT, Tt, tt respectively.

(B) terminal flowers

In F₂ generation, both the dominant and recessive characters are expressed and hence it will show both the types of flowers.

S.I is a coherent system of unit. In S.I system, all the derived units can be obtained by dividing and multiplying the basic and supplementary units and no numerical factors are involved. In case of CGS and MKS systems, when the derived units are obtained by dividing or multiplying, sometimes the numerical factors appear.

The unit of left-hand side (i.e. x) is metre so the units of cl² should also be metre. Since t² has unit of s² , so the unit of c is m/s² .

When the end of a glass-tube is heated the glass melts. Due to the surface tension, the molten glass tube tends to have minimum surface area. Thus, the molten glass at all points on the end of tube tends to take spherical shape and as such the end becomes round.

Given: 

Radius of atom, r_a = 1 Å = 10^-10 m

Radius of nucleus, r_n = 1 fermi = 10^-15 m

Volume of atom; \(V_1 = \frac{4}{3}\pi r^3_a\)

Volume of nucleus,\(V_2 = \frac{4}{3}\pi r^3_n\)

\(\frac{V_1}{V_2}\,=\,\frac{\frac{4}{3}\pi r^3}{\frac{4}{3}\pi r_n^3}\,=\,(\frac{r_a}{r_n})^3\,=\,(\frac{10^{-10}}{10^{-15}})^3\,=10^{15}\)

yes, because all the derived units in this system can be obtained by multiplying or dividing the certain set of basic and supplementary units.

The absolute pressure within the liquid at a depth h is p = p₀ + ρgh.

Since the excess pressure inside a bubble is \(\frac{2T}R\), the pressure inside the bubble is P_in = p + \(\frac{2T}R\) = p₀ + ρgh.+ \(\frac{2T}R\)

Candela and kelvin respectively.

No. 1 = A.U. = 1.496 × 10¹¹ m.

(mean distance of earth from the sun), 

1 Å = 10^-10 m. (atomic size)

The surface tension of oil is less than the surface tension of water. Thus when oil is dropped on the surface of water, it spreads in all directions due to the higher force of surface tension of water.

Pressure exerted by a liquid due to its height is called column pressure.

It indicates dry weather.

A storm is indicated.

The pressure exerted by column of a liquid equal to that of atmosphere depends inversely on density of the liquid. Because p = hρg or h ∝ 1/ρ (for a constant p). Since mercury is a most denser liquid available, therefore by using it, the barometric arrangement will be of very convenient size.

Suppose the atmospheric pressure is 1.01 x 10⁵ Pa. Then the height of water barometer is,

h_w = p/ρ_wg = {1.01 x 10⁵}/{10³ x 9.8} = 10.3 m

The height of mercury barometer is,

h_w = p/ρ_Hgg

{1.01 x 10⁵}/{(13.6 x 10³ x 9.8)} = 0.76 m

Thus, the tube required for water barometer should be long, which is very inconvenient, whereas the tube used in mercury barometer is small, which is convenient to use.

The average distance between the earth and the sun is called one Astronomical unit.

When tent cloth is coated with aluminium hydroxide, water does not stick to it. Thus, the coating of aluminium hydroxide prevents wetting of tent cloth.

The barometric height would decrease due to the pressure of the water vapours.

When the dead body decays, its volume increases. Thus, it becomes lighter than water and hence floats up. However, head being heavy cannot displace water more than its own weight and hence remains under water.

The upthrust of water apparently reduces the weight of man in water. So, it is easier for him to move the limbs in water than in air.

= 8.58 x 10^-6.

Liquid transmits pressure equally in all directions.

Data : d = 1 mm, v₀ = 2 m / s, η = 1.8 × 10^-5 N.s/m²

r = d/2 = 0.5 mm = 5 × 10 m^-4 m

By Stokes’ law, the viscous force on the raindrop is f = 6πηrv₀

= 6 × 3.142 (1.8 × 10^-5 N.s/m² × 5 × 10^-4 m)(2 m/s) 

= 3.394 × 10^-7 N

Changes in the angle of deviation as we increase

(i) The wavelength of incident light

As we increase the wavelength, angle of deviation decreases.

(ii) The refracting angle of the prism

The angle of deviation increases with the increase in the angle of prism.

The relation between the angle of incident (i), angle of emergence (e), angle of prism (A) and angle of deviation (δ) for a ray of light passing through an equilateral prism is

δ = (i+e) – A

Correct option is C) 30°

Correct option is D) All are correct

Reynold's number is a pure number which determines the nature of flow of liquid through pipe.

Osborne Reynolds found that if the free- stream velocity of a fluid increases when it moves relative to a solid body, a point is reached where the steady flow becomes turbulent. From experiments, he found that the transition from steady to turbulent flow depends on the value of the quantity \(\frac{v_0d}{η/p}\), where v₀ is the free-stream velocity, d is some characteristic dimension of the system, ρ the density of the fluid and η its coefficient of viscosity. For a sphere in a fluid stream, d is its diameter; for water in a pipe, d is the pipe diameter.

This dimensionless number, defined as Re = \(\frac{v_0dp}η\) is called the Reynolds number. In a system of particular geometry, transition from a steady to turbulent flow is given by a certain value of the Reynolds number called the critical Reynolds number. The free-stream velocity for this critical Reynolds number is called the critical velocity, V_critical = \(\frac{nR_e}{pd}\). For a given system geometry, the free stream velocity beyond which a streamline flow becomes turbulent is called critical velocity.

Steady flow takes place for Re up to about 1000. For 1000 < Re < 2000, there is a transition region in which the flow is extremely sensitive to all sorts of small disturbances. For Re > 2000, the flow is completely turbulent.

[Notes : (1) for “free-stream velocity”. (2) The dimensionless number is named after Osborne Reynolds (1842-1912), British physicist.]

The dimensions of Reynold's number is [M⁰L⁰T⁰].

The nature of graph is Straight line.

Devices used are:

Electron microscope, tunnelling electron microscope.

Correct option is: (A) cesium-133 atom

An expression for dynamic pressure is 1/2 ρv².

S.I. units is the short (i.e. abbreviated form) of system international (d’ unités) which is French for international system of units. It was developed and recommended by general conference on weights and measures in 1971 for international usage in domestic, commercial, industrial, scientific and technical works

The advantages in choosing the wavelength of a light radiation as a standard of length are as follows:

(a) The wavelength of light is not affected by time and environment. 

(b) This standard of length does not undergo any change with place.

(i) It can be easily made available in any standard laboratory as Krypton is available everywhere.

(ii) It is well defined and does not change with temperature, time, place or pressure etc.

(iii) It is invariable.

(iv) It increases the accuracy of the measurement of length (1 part in 10).

Rainbow is always formed in the direction opposite to sun. The position of red colour in the rainbow is at the top.

(C) The colour at position marked 7 is violet.