Practice Test - NEET MCQ

Explanation:

When a negatively charged conductor is connected to the earth, electrons will flow from the conductor to the earth. This is because electrons have a negative charge and they will be repelled from the negatively charged conductor and attracted to the positively charged earth. As electrons flow from the conductor to the earth, the negative charge on the conductor will gradually decrease until it becomes neutral.

• Option A is incorrect because charge flow does occur when a negatively charged conductor is connected to the earth.
• Option B is incorrect because protons have a positive charge and they are not free to move in a conductor.
• Option C is incorrect because electrons flow from the earth to the conductor, not the other way around.

As aluminium and copper are metals, their mobile electrons move under the influence of the external field until they reach the surface of the metal and collect there. External electric fields induce surface changes on metal objects that exactly cancel the field within. Since the field applied is same in both case, the induced charge will be the same.
Hence, the magnitude of induced charge in the aluminium will be the equal to that of copper.

Electric flux, Φ = −1.0 × 10³ N m²/C

Radius of the Gaussian surface,

r = 10.0 cm

Electric flux piercing out through a surface depends on the net charge enclosed inside a body. It does not depend on the size of the body. If the radius of the Gaussian surface is doubled, then the flux passing through the surface remains the same i.e., −10³ N m²/C.

Electric flux is given by the relation,

qϕ=q∈0

Where,

q = Net charge enclosed by the spherical surface

∈₀ = Permittivity of free space = 8.854 × 10⁻¹² N⁻¹ C² m⁻²

∴ qq=ϕ∈0

= −1.0 × 10³ × 8.854 × 10⁻¹²

= −8.854 × 10⁻⁹ C

= −8.854 nC

Therefore, the value of the point charge is −8.854 nC.

In case I :


In Case II :


From equations (i) and (ii),

Let m be mass of each ball and q be charge on each ball. Force of repulsion,


In equilibrium
Tcosq = mg ...(i)
Tsinq = F ...(ii)
Divide (ii) by (i), we get,

From figure (a),



Divide (iv) by (iii), we get

Since the charge –q is moving in elliptical orbit so to make its motion stable the total angular momentum of the charge is constant since it experience a centripetal force from the charge +Q so it follow the motion as the motion of earth around sun.

Acceleration 

This consists of two dipoles, –q and +q with dipole moment along with the +y-direction and –q and +q along the x-direction.


Along the direction 45° that is along OP, where P is (+a, +a, 0).

The correct answer is option B.

The I.U.P.A.C. name for Fe(C₅H₅)₂ is bis(η⁵ -cyclopentadienyl) iron(II) 
The oxidation state of iron is +2 and is written in parenthesis in roman numerals. Two cyclopentadienyl ligands are coordinated to Fe. The prefix bis indicates 2. η⁵ indicates that the cyclopentadienyl ligands are penta coordinates.

A complex compound in which the oxidation number of metal is zero is [Ni(CO)_4​]. In this complex, the oxidation number of both metal and ligand is zero.

The oxidation number of metal in the complexes K₄​[Fe(CN)₆​], K₃​[Fe(CN)₆​] and [Pt(NH₃)₄]Cl₂ are +2, +3 and +2 respectively.

Consider werner’s theroy

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

Δ_o value is directly proportional to energy and inversely related to the wavelength. Also, more the ligand is a strong field ligand More will be the value of Δ_o and lower will be its wavelength. Among the given complexes the strength of ligands are Br⁻ < H2O < en.

Since the emitted colours are red, green, blue the absorbed colours must be green,red,orange. Hence the  compound [M(H2O)6]²⁺, [M(en)3]²⁺, [M(Br)6]⁴⁻ are blue red and green respectively. Hence option B is correct.

Stem elongation is a kind of growth of stem.

Auxin and Gibberellin are known as growth hormones of plants. Therefore, stem elongation is affected by hormones Auxin and Gibberellin.

Most skeletal muscles are attached to bones by bundles of collagen fibers known as tendons. A skeletal muscle refers to multiple bundles (fascicles) of cells joined together called muscle fibers. The fibers and muscles are surrounded by connective tissue layers called fasciae.

Hinge joint occurs between humerus and radioulnar.
A hinge joint is a common class of synovial joint that includes the ankle, elbow and knee joints. Hinge joints are formed between two or more bones where the bones can only move along one axis to flex or extend. The elbow is a hinged joint made up of three bones which are the humerus, ulna and radius.

Myology is the branch of biological science in which different aspects of muscles are studied.

Trachea divides at the level of 5th thoracic vertebra into a right and left primary bronchi.

After a forceful expiration gaseous exchange continues uninterrupted because there is always a residual volume of air that continues the diffusion of gasese.

Vital capacity includes ERV, TV and IRV or the maximum volume of air a person can breathe out after a forced inspiration.

• In the tissues, where low pO₂, high pCO₂, high H+ concentration and higher temperature exist, the conditions are favourable for dissociation of oxygen from the oxyhaemoglobin.
• This clearly indicates that oxygen gets bound to haemoglobin in the lung surface and gets dissociated at the tissues. 

• The nodal musculature has the ability to generate action potentials without any external stimuli.
• The number of action potentials that could be generated in a minute varies at different parts of the nodal system.
• The SAN can generate the maximum number of action potentials and is responsible for initiating and maintaining the rhythmic contractile activity of the heart.
• Therefore, it is called the pacemaker.

• Platelets, also called thrombocytes, are cell fragments produced from megakaryocytes.
• Platelets can release a variety of substances most of which are involved in the coagulation or clotting of blood.

The hepatic portal vein carries blood from the intestine to the liver before it is delivered to the systemic circulation.

Prehypertension is defined as a systolic pressure from 120–139 millimeters of mercury (mm Hg) or a diastolic pressure from 80–89 mm Hg.

A special case of Rh incompatibility (mismatching) has been observed between the Rh^-ve blood of a pregnant mother with Rh^+ve blood of the foetus.