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(1) Can you see the nearby objects? 

(2) Can you see the distant objects? 

(3) Can you read the book comfortably? 

(4) From which distance, you can see the objects clearly?

(1) Ethanoic acid is used as preservative in pickles in the form of vinegar. 

(2) It also used as good cleaning agent.

Ionization energy : The energy required to remove one electron from the outermost orbit or shell of a neutral gaseous atom is called ionization energy. 

Factors that effect the ionization energy : 

(1) Nuclear charge, 

(2) Screening effect 

(3) Penetrating power of the orbitals 

(4) Stable configuration 

(5) Atomic size.

(1) Anomalous pair of elements : Certain elements of highest atomic weights precede those with lower atomic weights. 

Ex : Tellurium (At.wt. 127.6) precedes Iodine (at.wt.126.9).

(2) Dissimilar elements placed together : Elements with dissimilar properties were placed in same group as sub-group A and sub-group B.

Ex : 

(1) Alkali metals like Li, Na, K, etc. of IA group have little resemblance with image metal like Cu, Ag, Au of IB group. 

(2) Cl is of VIIA group and 'Mn' is of VIIB. But chlorine is a non-metal where Mn is a metal. 

1. The nucleus and the electrons in the inner shell remain unaffected when atoms come close together. 

2. But the electrons in the outermost shell (valence shell) of atoms get affected. 

3. The inner shell electrons are strongly attracted by the nucleus when compared to the valence electrons. 

4. So electrons in valence shell (valence electrons) are responsible for the formation of bond between atoms.

Solar Cell – A solar cell is a device which converts the incident solar light energy directly into electrical energy in DC form.

Solar Panel – In a solar cell panel a large number of solar cells are joined together in a definite pattern to provide greater power at higher voltage.

Advantages of solar cell –

• They directly utilize solar energy.

• They can work satisfactorily even in diffused radiations.

• They need no maintenance.

• They do not cause pollution

The soil which originate under tail grass prairie vegetation is called Chernozem soils.

d). ionic bond

Economically exploitable lignite occurs in Tamil Nadu.

Lateritic is soil types of India is rendered infertile by the presence of excess iron.

(C) ovary and radicle.

(b) Clayey soil

Hampi is in Karnataka.

(b) Haematite

C) Ovary and radicle

Singhbhum where copper ore is mined is in Jharkhand.

C) 2NaOH + H₂SO₄ → NaSO₄ + 2H₂O

Bauxite is the ore of Aluminium.

The answer is C) 50 Hz.

Eye lens is transparent fibrous jelly-like material bi-convex lens. 

Ciliary muscles : These muscles hold the lens in position. The images of the objects at different distances from the eye are brought to focus on the retina by changing the focal length of the eye-lens, which is composed of fibrous jelly-like material, can be modified to some extent by the ciliary muscles.

D) Emulsification

B) Aluminium

About 97% of the O₂ that diffuses into the blood combines with haemoglobin of RBCs forming an unstable compound called oxyhaemoglobin. The remaining 3% O₂ dissolves into water of plasma. 70% of CO₂ is transported from tissues to lungs in the form of bicarbonates dissolved in blood plasma. About 23% of CO₂ is transported to lungs in the form of carbamino-haemoglobin. 

(a) Na, Si, Cl No, 

because there physical properties are not same although the atomic mass of silicon is average of atomic mass of sodium and chlorine.

(b) Be, Mg, Ca Yes, 

because they have similar properties and mass of Mg is roughly the average of atomic mass of Be & Ca.

Name - sodium 

symbol- Na 

Electronic configuration - 2,8,1

D) All the above

The following are the environmental friendly ways we can follow: 

I. Planting more number of trees to reduce the abundance of air pollution, 

II. Reducing the use of fossil fuels in public transportation, 

III. Applying proper waste disposal strategies, 

IV. Composting of bio- degradable waste, 

V. Providing shelter for stray animals.

(a) less nitric oxide is available to react with ozone. 

Limitations of Mendeleev’s periodic table : Inspite of many advantages, the Mendeleev’s periodic table has certain defects also.

Some of these are given below -

(i)  Position of hydrogen : Position of hydrogen in the periodic table is uncertain. It has been placed in 1A group with alkali metals, but certain properties of hydrogen resemble those of halogens. So, it may be placed in the group of halogens as well.

(ii)  Position of isotopes : Isotopes are the atoms of the same element having different atomic masses. Therefore, according to Mendeleev’s classification these should be placed at different places depending upon their atomic masses. For example, hydrogen isotopes with atomic masses 1, 2 and 3 should be placed at three places. However, isotopes have not been given separate places in the periodic table because of their similar properties.

(iii)  Anomalous pairs of elements : In certain pairs of elements, the increasing order of atomic masses was not obeyed. In these, Mendeleev placed elements according to similarities in their properties and not in increasing order of their atomic masses.

For example : 

• The atomic mass of argon is 39.9 and that of potassium 39.1. But argon is placed before potassium in the periodic table.

It contains human protein, α-lactalbumin (2.4 g/l) that is nutritionally more balanced for human babies than normal cow-milk

a. E = P X T 

SO, E = 3X2 = 6 kWh  

Cost of buying electricity from the main electricity board = 6 x 3.50 = Rs. 21.0

b. To reduce the boiling time using the same mains supply, the rate of heat production should be large. We know that P= V 2 /R. Since V is constant, R should be decreased. Since R is directly proportional to l so length should be decreased.

Oxygen molecule splits into atomic oxygen(O) at higher levels of an atmosphere because of higher energy of UV radiations: 

So, O₂ ⇾ O + O 

Each of the atomic oxygen then combines with another oxygen (O₂) molecule which gives rise to ozone (O₃) 

O₂ + O ⇾ O₃(ozone).

Ozone layer helps in preventing the entry of harmful UV radiations on earth. Ozone is produced by reaction of O₂ molecules with O free radicle in the presence of solar radiation. Chloro fluoro carbons (CFC's) are synthetic chemicals responsible for depletion of ozone. Methods to reduce CFC emission. i) By reducing the use of AC, fridge , perfumes, etc. 

5 ohm, 10 ohm and R₁ are in series 

1/R_p = 1/5+1/10+1/R₁ 

1/R_p = (2+1)/10 + 1/ R₁ 

= 3/10 +1/ R₁ 

1/R_p = (3 R₁ +10)/10 R₁ 

R_p= 10 R₁ / (3 R₁ +10) 

Now, 6 ohm, 6 ohm and R_p are in series 

Thus, 

R_eq = 12 + 10 R₁ / (3 R₁ +10) ------------------ (1) 

V = I R_eq 

From the circuit 

R_eq = 30/2 = 15 A ---------------(2) 

Equating (1) and (2)

12 + 10 R₁ / (3 R₁ +10) = 15 

10 R₁ / (3 R₁ +10) = 3 

10 R₁= (9 R₁ + 30) 

Thus, R₁ = 30 ohm.

R = 2 m

α = 0.30 rad/s²

\(\vartheta\) = 7m/s

We use the formula for kinematics of rotational motion to solve

\(\omega^2-\omega_0\,^2\) = 2α(θ - θ₀)

∵ \(\omega_0 - 0 \)

\(\omega^2 = 2 \times0.30(\theta -\theta_0)\)

∵ \(\vartheta = r\omega\)

\(\omega = \frac{\vartheta}{r}\)

⇒ \(\frac72 = 3.5 \) rad/s

(3.5)² = 2 x 0.30 (θ - θ₀)

(θ - θ₀) = \(\frac{12.25}{0.6}\)

(θ - θ₀) = 20.41 rad

Then

S = rθ

S = 2 x 20.41

S = 40.83 m

a. Tt 

b. Traits like ‘T’ are called dominant traits, while those that behave like ‘t’ are called recessive traits./Alternatively accept the definition of dominant and recessive traits with examples of T and t respectively /Alternatively accept the law of Dominance with examples of T and t. 

c. Out of 800 plants 600 plants will be tall and 200 plants will be small , 1 TT: 2Tt: 1tt 

OR 

In the cross between Tt X tt, 400 Tall (Tt) and 400 short (tt) plants will be produced.

(a) Sir is trying to demonstrate the principle of Electromagnetic induction.

(b) There will be induced current in the coil due to relative motion between the magnet and the coil. Changing the magnetic field around the coil generates induced current.

(c) Using a stronger magnet, using a coil with more number of turns.

a. Sir is trying to demonstrate the principle of Electromagnetic induction. 

b. There will be induced current in the coil due to relative motion between the magnet and the coil. Changing the magnetic field

c. sing a stronger magnet, using a coil with more number of turns.

OR

When the magnet moves into the coil, the ammeter shows a momentary deflection towards one side say left.

When the magnet moves out of the coil, the ammeter shows a momentary deflection now towards right.

This is due to changing magnetic field /flux associated with the coil as the magnet moves in and out.

Alternatively, the flux increases when the magnet goes in and it decreases when the magnet goes out.

B) It's OK. My sister took him out for a walk.

(i) A. Dispersion

(ii) B. Red colour is monochromatic.

(iii) D. Different wavelengths travel at different speeds in the glass.

(iv) C. Rainbow.

 CO₂ (CARBON DIOXIDE) AND H2O (WATER)

B) She had hurt her arm.