Explore topic-wise InterviewSolutions in Current Affairs.

Volume of the oil is conserved. Radius of oil drop = R = 1 mm

Radius of the oil film on the water surface is r = 20 cm

The thickness of the oil film formed represents the size of the oil molecule.

(4/3)πR³ = πr² × size of a molecule

⇒ Size of a molecule = (4/3) x (R³/r²)

= (4/3) x ((1 x 10^-3)³)/(20 x 10^-2)²)

= 0.33 × 10^-7 m

The correct option is A) Diffraction.

The phenomenon of bending of light ray at sharp edge is called Diffraction of light.

A. Diffraction

The correct option is D) Balmer series.

Balmer series falls in visible region of hydrogen spectrum.

 D. Balmer series

The Correct option is B.(11001)₂

The correct option is A) Coulomb/metre².

Coulomb/metre² is the unit of surface charge density.

D. 36π  x 10⁴ Nm² /C

The correct option is B) q/ ɛ_o.

By Gauss law pi = q/ ɛ_o.

(a) equal amounts of thermal energy must be produced in the resistors
(b) unequal amounts of thermal energy may be produced

(b) A is correct but B is wrong.

(a) there will be no neutral temperature
(b) there will be no inversion temperature

Correct option is (B) greater than velocity of light in denser medium

Planck’s quantum theory:

i. Max planck proposed quantum theory in order to explain black body radiation.

ii. According to Planck’s quantum theory, light is propagated in the form of packets of light energy called quanta.

iii. Each quantum of light (photon) has energy, E = hv

where, h = Planck’s constant

= 6.63 x 10^-34 Js

v = frequency of light

Drawbacks of Newton’s corpuscular theory:

i. It could not explain partial reflection and refraction at the surface of a transparent medium.

ii. It was unable to explain phenomenon such as interference, diffraction, polarisation etc.

iii. This theory predicted that speed of light in a denser medium is more than the speed of light in a rarer medium which was experimentally proved wrong by Focault. Hence Newton’s corpuscular theory was rejected.

iv. When particles are emitted from the source of light, the mass of the source of light must decrease but several experiments showed that there is no change in the mass of the source of light.

because density and temperature of isotropic medium are same throughout.

iii. Different colours of light waves are due to different wavelengths of light waves: Each wave has its own wavelength. As the wavelength changes, its colour and frequency also changes. This is indicated by change in the colour.

iv. The material medium is necessary for the propagation of wave: Periodic disturbance is created in the medium at one place which is propagated from that place to another place. The medium only carries disturbance and hand it over to the next particle. To explain the propagation of light waves through vacuum, Huygens suggested the existence of a hypothetical medium called ‘luminiferous ether’.

Note: Light waves are assumed to be transverse whose speed in a hypothetical medium is given by v = \(\sqrt{\cfrac{E}{\rho}}\), where E and ρ are elasticity and density of the medium respectively.

2,3 Dimethylpentane

2,5 Dimethylheptane

One mole amount of substance that contains as many particles or entities as there are atoms in exactly 12 g of the 12 C isotope.

It is based on the principle that the elements present in the organic compound are converted from covalent bond into ionic bond on fusing the compound with sodium metal.

2Na + S → Na₂S

No, because calcium is less reactive than sodium.

No, because potassium is more reactive than sodium.

(CH₃)₃C⁺ has nine alpha hydrogens and has nine hyperconjugation structures while CH₃C⁺H₂has three alpha hydrogens and has three hyperconjugation structures, therefore (CH₃ )₃C⁺ is more stable than CH₃C⁺H₂.

+E effect Operates during the attack of proton on ethane molecule.

The shared carbon atoms are electrophilic centres as they will have partial positive charge due to polarity of the bond. CH₃ HC = O, H₃ CC = N, H₃ C – I.

The electron deficient molecules or positively charged ions which are capable of accepting on electron from substrate molecule are called electrophiles.

Positive electrophiles: H⁺, Cl⁺, Br⁺, NO₂, N⁺ = O, R⁺(carbocations) etc. 

Neutral electrophiles: SO₃, BF₃, AlCl₃, Cl

A reaction intermediate formed by heterolysic fission of a covalent bond which contains one negatively charged carbon with eight electrons in its valence shell is called carbanion.

The heterolytic cleavage of a covalent bond as indicated in the following reactions gives carbanions.

Example:- CH₃ - MgI → CH₃^- + MgI

A functional group is defined as “an atom or group of atoms present in a molecule which determines most of the chemical properties of the particular class of organic compounds”.

Example: CH₃ – OH methyl alcohol.

The hydrides of carbon (hydrocarbons) and their derivatives are called organic compounds.The branch of chemistry which deals with these compounds is called organic chemistry.Berzelius (1808) defined organic chemistry as the chemistry of substances found in living matter and gave the vital force theory. Synthesis of urea. the first organic compound synthesised in laboratory, by Wohler. gave death blow to the vital force theory.

General Characteristics of Organic Compounds are:

1. These are the compounds of carbon with H, 0, N, S, P, F, CI, Br and 1. 

2. These are generally found in living organisms. e.g., carbohydrates, proteins etc. 

3. These may be gases, liquids or solids .

4. Being covalent in nature, these have low boiling point and melting point and soluble inorganic solvents. 

5. These are generally volatile and inflammable. 

6. They do not conduct electricity because of the absence of free ions. 

7. They possess distinct colour and odour.

Characteristics of Free Radicals

(i) Free radicals are generally electrically neutral. 

(ii) They carry on odd (unpaired) electron. 

(ii) They are highly unstable. 

(iii) They are short-lived. 

(iv) They are highly reactive species due to the presence of odd electrons. 

(v) They have a tendency to pair up with the odd electrons to form a covalent bond. 

(vi) They are generally formed either in presence of U.V. or visible light or in the presence of peroxides.

Correct option is (d) Empowerment

Correct option is (a) Great person theory

Correct option is (d) Self-inside

The property of self combination (or linking) of carbon atoms to form long chains is useful to us because it gives rise to an extremely large number of carbon compounds (or organic compounds). This is known as catenation.

(c) Indigofera

A drup develops in Mango.

Correct Answer is : (c) Six

(d) Placentation in primrose is basal

(a) Axillary buds

Hermaphrodite Eg. Earthworm, Leech.

(a) Dioecious

Answer is Bulbil

The nervous system stimulates stomach muscle into action.

1. When the food is in the oral cavity, the nerves in the cheek and tongue are stimulated. 

2. These carry messages in the form of nerve impulses to the brain. 

3. They messages are transmitted from the brain, to the wall of the stomach, and stimulate the gastric glands to produce gastric juice.

POEM: 

Life is a process of discomfort and pain. Learn to handle it all with courage and sane Remember the bliss waiting for you Nutrition, excretion, respiration all are essential in our life. 

Reproduction makes our species go on and on forever. 

Autotrophs and heterophs are brothers. 

Depend on each other In a systematic way. So have courage to learn more tricks. Search for happiness. In life that survive.